The pyro stuff is just a lot of fun, building the mmph is tricky, but crits are nuts. Seems balanced, not being able to airblast is huge.
Not sure about the spy-cicle, I've been using it with invisi watch, and it seems fair, pyros can really shutdown spies, which isn't fun when they dedicate their entire game to mindlessly flaming around looking for you (uninstallthefuckinggame) and the ice will allow you to escape being lit up, and cloak away, but the if pyros onto you it wont be difficult for him to light you up after 2 secs, and you wouldn't be able to trick stab the pyro.
Deadringer just kills it though.. it's just godmode, because pyros could light up deadringer spies and after waiting for the insane damage resistance to end the pyro could finally kill them. Now the DR spy can simply shrug the flames off, so he basically has a third life before he even finds an ammo pack. Also because DR spies will be carrying the enforcer they can actually gun down the pyro during his flame invincibility, because all fire damage is resisted. So the pyro trying to bring such a spy under control is out of the question. The another thing is the knife leaves ice sculptures, this is bad when you don't have the DR because people will realise there is a spy around, It doesn't matter with DR because there isn't any need for spy play or being sneaky, if the jigs up, you deadring out of there, or gun them all down with the enforcer, it's so funny to do, but so unfair when it's you being shotdown.
Yeah I don't like the deadringer
but I use to use it a lot, and I tried to use the other watches because it just didn't feel like playing spy, I just felt like I was being an annoying turd killing people because they couldn't kill me, not because I had played cleverly so they didn't spot me in the first place. I didn't realise how irritating and unfun to play against I was being, until I had my own issues with these powerhouse "here I am!!" spies.