I'm actually surprised Steve has no reviews. Guess I'll be the first to comment on how powerful he is.
Before he got rotated out, Steve was a big part of my LGS meta. If you weren't running , you were instead playing Panic (but don't actually hang him) to host Steve, and for good reason. Recycling cards is powerful as the Runner; there's a reason why Levy AR is restricted. The only downside to his ability is that the Corp picks which card you get back while the other is RFG'd. One of the guys at my LGS would actually say "Sure Gamble or Sure Gamble?" when forcing the Corp to let him recycle a Sure Gamble. Steve is immensely powerful in any deck simply because you can recycle basically anything; it just depends on what the Corp deems to be more dangerous to let you keep. The only stipulation is that it's only for the first run on HQ each turn. Of course, Criminals know how to bypass your ice. The fact they can recycle any of their cards, especially those with powerful trash abilities, should be scary for any Corp player.
So why Steve over other another Criminal? Someone like Los or Nero would have a decent one-per-turn ability, but after a certain point, Los is as blank as an after-game-start Val, and Nero, in my opinion, is more for face-checking. Gabe has a decent ability of his own (and is a great teaching tool for Runners), but after a certain point, the credits aren't as useful as getting certain cards back, especially in the late game when you need another Sure Gamble or a previously trashed program or hardware. Of course, you could play my least favorite Runner ever, but I refuse to discuss her. Of course, you can only play Steve in the Eternal and Snapshot formats now. Considering how big he was at my LGS, I kind of hope Steve gets cycled back in sometime in the future.