After playing for two days, I can give my impressions so far:
First off, don't take any of this criticism too hard. This game is excellent, and it is the most fun I've had getting into a game like this since Oblivion. Of the three games that I bind together, (Fallout 3, STALKER, and Borderlands) I'm having the most fun with this one so far. That being said, here is a jumbled summary of what I think.
For starters, the game runs very smoothly. I haven't had one crash, lock-up, or freeze the entire time I've played. The music fits the atmosphere very well, and it reminds me of the old Fallout soundtracks, specifically the hand drums. The graphics are good, but I still don't know if I like the whole "comic book/cel-shading" thing that some newer games are doing. It looks better here than in Halo ODST, but I'm still not warmed up to it yet. I have seen a few odd bugs here and there, but nothing that made me ragequit. Usually, they just make me laugh and want to play again. I've seen enemies spawn two feet away from me, since the day/night cycle had reset while I was walking through a clan territory. I've gotten stuck in-between rocks, with no way of getting out. I had to take my shield off and throw grenades at my feet to continue. The only things that sort of annoy me are not glitches, but game mechanics that start to get old after a while. For example, the way that Skags will wait to come out of their dens until you've killed enough of them. One thing that I specifically love about this game is the "Second Wind" feature that you get if you can pull off a kill before dying. This adds a whole new level of strategy to gunfights: Rather than killing a bunch of tough enemies one at a time, I try to severely weaken a few so that I can pull off a last chance kill if I need to. I like the innovations that I see in the weapons, but there's still a bit too much stat-checking for me. I hate having to spend a few minutes deciding if one point of accuracy is better than one point of reload time. I'm noticing a trend in the games that I've been playing lately, specifically this and Dragon Age. They both seem curiously like Massive Multiplayer Offline games. I'm not a fan of MMOs, because I think they get stale too fast. Hopefully this trend is temporary.
Anyway, those are just a few of my scattered thoughts. All in all, like I said earlier, this is a very fun game right now, but I'm not convinced yet that it has the staying power of something like Oblivion.