OK, I'm becoming more and more proficient at HoN, as evidenced by my recent "leap" from a skill rating of below 1280-something to over 1400 (for reference: you start with 1500 ;-).
The skill rating system is a bit retarded - when you're a newbie it's easy to earn and lose points and then, as you "level up" your account, the changes are smaller. It makes sense for DotA veterans but when you're a complete newcomer like me you will at first drop in the rankings A LOT and then it will be hard to get back up. With skill ratings like 1200 or even 1300 you will be kicked from games, people won't join your team and stack against you and whatever. The player base in HoN is really nasty sometimes. :-\
So far I haven't really tried out every hero in the game, only some. I think I should stick to several characters like in fighting games, although it's best to pick a couple from each category, so you can counter the enemy team and aren't blocked if somebody "steals" your character.
I am familiar with the following characters now:
Defiler - good early/mid game ganker and mid/late game pusher - late game her role diminishes to clearing out creeps around teamfights with her ultra and silencing enemies. Her damage output becomes negligible. Upside is - people will usually tell you to solo mid with her, so you level up quickly and Defiler isn't killed that easily since she can silence her attackers and heal with her Ultimate, which can be kept up even on the run. I remember a Swiftblade player who kept pestering me throughout the game, trying to follow me with Blade Frenzy, which makes you immune to magic - too bad Defi's ultra deals normal damage. He failed three times in a row and died - "If at first you don't succeed, you fail" ;-)
Swiftblade - One of my favorite carries (heroes that have abilities that scale well with items and deal more damage as the game progresses). He has no stuns, silence or even slows but isn't that weak early in the game, since his blade frenzy can harass enemies quite nicely if you have a good lane partner. Also, it's immensely useful for farming creeps and even late in the game gives you magic immunity for quite a long while, so you can escape fights. His ultimate is lulzy, since it relies on his own attack damage and regardless of the stage of the game deals ridiculous amounts of damage if the enemies don't have creeps around them (since the ultimate attacks random targets). It's so funny to target a greedy enemy who thinks he's got you but separated from the rest with the ultra - instant karma. ;-)
Pestilence - A semi-tank-semi-carry with great mobility and an awesome spammable AoE stun. I usually don't kill that many people with him but get TONS of assists (like 20+ in a game 0_o). His Ultimate reveals stealthed units in addition to lowering their armor for epic Scout and Night Hound pwnage. A great addition to any team, although lots of ranged heroes and/or Arachna can counter him pretty badly, if the enemy knows what he's doing.
Hellbringer - Basically a support hero, who can push very nicely with his ultimate which summons a demon. Late in the game the demon is only good for the initial stun, since he will die in mere seconds. He has lots of spells that retain their usefulness throughout the game though - reducing the enemy's magic armor, slowing them down and even a poison-like spell for early lane harassment.
Soulstealer - Nice hero who is very strong mid-game but becomes less useful with time, IMHO. The only late-game skill he has going for him is the armor reduction on enemies. His ultimate is INSANELY powerful before very, very late in the game but requires good positioning. He has a funny AoE spell that has three separate ranges and three separate cooldowns for them - he can farm creeps like no one in the game. If you need an item, you go out and clear like 2-3 creep waves and have it immediately. If you're good at targeting the spell also reinforces your amazing mid-game ganking potential. First ultimate, which deals like 600 damage to everybody in the area, if you position yourself correctly, and then some Dark Hands - you can bring down any hero in mere seconds. Ah - he has this "Soulsteal" ability too, which increases his damage and feeds his ultimate. For every enemy/creep he kills, he gets +2 damage (up to +60). If you're good at last hitting/denying, you are absolutely epic in the middle lane - the better you are at last hitting/denying initially, the easier it becomes later.
Madman - Currently my favorite carry. He deals INSANE damage mid-late game and also has a stun ability that both helps your team and makes it virtually impossible for the enemy to escape. His only weakness is being less useful early in the game and being hopeless at lane pushing.
Slither - A good early/mid game harasser/ganker and late-game pusher. His ultimate is crazy early-mid game but can't kill targets - only bring them down to 1 hp. I haven't played him for a while, so I don't remember him that much.
Pharaoh - Again, haven't played him for a while but I remember him as being quite lulzy. He requires a LOT of precise timing and targeting and good multitasking abilities, since he has 4 active spells, one of which he can cast at ANY location on the map. Definitely a hero I want to learn properly some day, since he is quite nice in ganks throughout the game because of the funny ring of mummies snare and his stuns. He can also defend a lane without being in it with his aforementioned infinite range spell.
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Now to the "bad" heroes. That is, heroes I have tried and failed with - not necessarily bad themselves (with the exception of Night Hound ;-)
Thunderbringer - I might try him out again some day, Crackhead is awesome with him. I'm not in the right mind-set for him though since he is basically a "hero sniper". A good Thunderbringer player should be able to amass more kills than probably any other hero in the game and make the enemy team lose simply by the constant drain on their money. I like to have him on my team, fear him on the enemy's team if he's good but personally absolutely suck with him. ;-)
Night Hound - Oh God, a typical noob hero. I was like everyone else, going "OMFGWTFBBQ, he can be invisible permanently", however, experienced teams will have means to detect him and he is much, much less useful than almost any other carry in the game. At least he has this AoE slow/silence spell but I rarely see people falling for it - they simply quickly disperse. He doesn't have stuns, doesn't deal epic amounts of damage like other carries, sucks at pushing and very often ends up being in a team with lots of kills but which still loses the whole game.
Jerziah - Another of these "I need to learn him" heroes. A good Jereziah is often what makes or breaks a game. He is a good pusher and arguably the best support hero/tank in the game but you have to know how to play him. I saw Jereziahs who couldn't be killed despite 4 people targeting him, sadly I'm not one of them. Early in the game he's an awesome lane partner, late in the game he is good at pushing and keeping everybody alive in team fights.
Electrician - Supposedly a good early game harasser, for me he was a good early gamer funeral. With experienced teams (and clueless enemies) he can be a good disabler and tank but I don't get him, neither do I really want to.
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Heroes I've seen people do wonders with:
Valkyrie - Seems a good ranged carry with stuns and escaping abilities. Also a pushing spell. For pure hero killing Arachna seems to be the better choice then.
Zephyr - If you know what you're doing he can literally turn into an unkillable death machine mid-late game. I had the fortune of playing with a very good one - both on the same team and against me - and he carried the team he was on to victory on both occasions. Then again I saw people fail with him a lot too. ;-)
Behemoth - A popular choice due to his mass stun abilities - and they allow you to cut off an enemy from escaping too. Probably the best gank initiator in the game. If you are laning against Behemoth and somebody calls that middle lane is missing, then chances are you will be ganked. If nobody calls miss, then you are most likely dead. ;-)
Arachna - Definitely the best ranged carry in the game. She wreaks HAVOC among melee heroes and makes sure that no one will ever escape a gank without some kind of blinking ability.
Puppet Master - Good disabler. Has some pushing ability too. His voodoo puppet skill is nice but your team mates have to know how to use it (attack the puppet instead of the target it's been cast on). He fails or wins depending on how good the rest of the team is.
Glacius - Has an aura that enhances mana regen ON THE WHOLE MAP for his team. Is relatively underpowered but his team-mates LOVE him. He can also disable a bit in ganks, so he's overall a nice support hero.
Succubus - BEWBS! Just ask YellowGoudvis how awesome she is. He transformed from Magebane failure into instant team-hero in a matter of like two matches. Her disables are INSANE and she can basically win any 1on1 duel you throw at her, provided she isn't taken by surprise and has enough mana/skills not in cooldown.
Accursed - Basically like Jereziah with completely different skills and yet similar results. One of the best support heroes/tanks in the game. A good Accursed usually makes or breaks the game but doesn't get many kills.
Magmus - Don't get me started. Like someone on the forums once wrote, his strategy involves "rolling your face on the keyboard; everybody dies". ;-)
Definitely have to learn him. An INSANELY powerful early/mid game hero, who still has some potential because of his stuns later in the game. I should learn him.
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Heroes I've mostly seen people fail with:
Scout - Scout, SCOUT, S C O U T! Seriously! I have seen very good Scout players, who placed lots of wards, SCOUTED (*doh*) the map for ganks/gank opportunities and helped their team to the best of their ability but most of the players just sit there invisible and wait for somebody's HP to get into red territory only to kill-steal. Then they vote to concede lost games in which they still have like a 2:1 K:D ratio. ;-)
GET THE FUCK OUT! :-P
If you're a newbie NEVER EVER pick Scout. He is very easy to play as if you ONLY care for your K:D ratio and team losses don't bother you but he actually is FAR better in the hands of an expert who knows how to play the game with other heroes. You will never learn how to play HoN properly by using only Scout - AND on top of that experienced teams will absolutely OWN you when they start to carry means to detect invisible heroes.
Magebane - The reason why Goudvis has such a low skill rating. ;-)
Seriously - he probably the weakest early-game hero there is and even late in the game other carries are FAR better. I've never ever seen a victory that was brought on mainly by Magebane but I've seen people fail with him badly.
Chronos - A VERY late game carry. Usually his team either wins or loses by the time he manages to get his optimal gear - then he becomes an unstoppable force of nature. Before that, uhm, game over man, game over. You can be successful with him in pub games which tend to drag on for quite a while if the rest of the team is competent enough to play 4vs5 (figuratively speaking) for 75% of the game. ;-)
What I'm basically saying is: you are unlikely to see someone exclaim: "Wow, we wouldn't have won if it weren't for Chronos!". ;-)
Legionnaire - I think there really are far better tanks than him and his insta-kill ultimate requires good battle orientation. Needless to say I usually see people failing with him although he's a good pusher and a good early game laner.
Phew - what a lengthy post. :-D
P.S. Your mileage might vary if you're playing a lot of 1on1 matches or easy mode, neither of which is the "real" HoN. *wink at you know who you are*. :-P
P.P.S. I'll post it as a blog entry too, so that we have some new content on the front page. ^^