I love this guy. He turns the game on its head.
His signature icebreaker, Endless Hunger, gets through an astonishing number of ice for dirt cheap. Particularly when paired with e3 Feedback Implants. On the other hand, ice that anyone else would find trivial, he is powerless against. (Nothing quite like being kept out of a server by a 0-strength Resistor)
Hunting Grounds means that a lot of "guaranteed" ice suddenly becomes a lot less valuable. Tollbooth becomes far less taxing. Pop-up Window suddenly loses half of its value. Grail ice is all single-subroutine, and poor Komainu and Troll are left basically blank.
His signature console, Heartbeat, offers unprecedented levels of damage protection. He is not easy to flatline, and having something that can fend off brain damage as easily as net damage is a little crazy.
And if the board gets out of hand, he's the only one who can easily afford to include a few copies of the game-changing Apocalypse card without spending influence. So he's likely to have a few of those about as well, wiping away glacial scoring servers and horizontal asset spam with equal ease.
His ID ability allows him to easily keep his icebreaker and console fed. 25 influence gives him a lot of room for goodies. Unfortunately though, he needs it, because his "no non-virtual resources" limitation actually turns out to be, well, extremely limiting.
Most of your influence budget will most likely go to card draw and economy. Without being able to install Daily Casts or Armitage Codebusting, you're limited to mostly event-based econ. You need solid card draw to power his ID ability, (which in turn powers everything else he has) but the glamorous Earthrise Hotel refuses to serve sentient internet viruses, he can't really form Professional Contacts, and Drug Dealers won't even give him the time of day. Most likely you'll end up having to import Quality Time, Diesel, or possibly even Safety First.
He definitely has his flaws. I don't think he (or any of the neutral runners from Data and Destiny, for that matter) will ever really become top tier decks. But the bottom line is: even so, he forces the corp to play a very different game than the one they were probably banking on, and that can be a pretty useful thing in a runner.