FF Tachyon - She was amazing, nearly broken. Even against Deadline who kept trying to shuffle her deck, she easily did the most damage. Any damage boost at all takes her from good to absolutely insane.
FF Legacy - I didn't use his environment control much with Argent on board, but he got set up awesomely fast. He has so many great cards that only see play late game since his deck is so strong, extra plays getting them early left him a powerhouse!
PW Argent - His new power was nice for a turn or two... but he's the Argent so once he got some instruments going, it was less amazing.The strength boosts elsewhere on the team hurt it a bit too. I can see him being amazing with someone like A/Z, but I think I still like the PW version best. I'm going to end up playing Kvothe an awful lot because I LOVE his new art.
Cosminfinitor - well, I smashed myself for 8 damage turn 1, but managed to survive the game at 3 hp. He was really fun, but also really, really suicidal. He'll be amazing against villains who wreck his toys or if you see a better power early.
FF Bunker - I tried him twice because he was so fun. This allows me to really explore his control options, as I'm not just digging for a gun. He's... really fun and strong in a bigger party, great for cards like Don't Dismiss Anything, PW Fanatic, and Gimmicky Character. This is my favorite promo so far.
Extremist Sky Scraper - Another I tried twice. Game was in the Enclave, so I made SS big and just tossed endangered species at the villain all game. The second game, I managed to switch a lot more between sizes which was super fun. I really like how just staying in normal is more viable and how many cool tricks flipping between sizes opened up. This is a seriously complex hero though.
New Parse - She was okay... got set up really fast, but was constantly short on cards. That may be variance, but without more cards being fed, the discard is a bit tough.
Who have you tried and what do you think?