I've finished my first playthrough, clocking in at 80 hours. But I faffed about a lot with stealth and never used fast travel.
Fittingly, the game crashed during the credits...
It's a shame they released it in such a state, really. It's an excellent game underneath all the bugs, crashes, and unpolished stuff. Cool story, some memorable characters, genuinely brilliant cyberpunk atmosphere.
For those who haven't played it yet: if you're not a huge cyberpunk fan - either of the genre itself or the RPG -, wait a year with this. If you are, play it now anyway - it's still worth it to our kind.