I'm really tempted to try out this game. But it looks like a verry dangerous time sink :P At least judging from my past experiences with nethack and cataclysm:dda
Well, nearly all games are pretty much time sinks if you allow them to become such, especially those which you're well-versed to. Speaking for myself, even though i dig this particular game as a whole (for what it's worth it, i have little experience in the genre), i find that my usual CoQ session lasts about an hour give or take.
Sure, but some games more than other ;) For instance, on a day off I can sit the entire day playing Civilization without skipping a beat, but more than an hour or two/three worth of a good FPS is a bit much.
By the way, if you're interested in checking out something else in the genre that is a very good post apocalyptic survival game, then take a peak at Cataclysm:DDA. The game is still being continuously worked on and it's got a pretty active community. Crazy complex though.