I haven't managed to finish Fallout: New Vegas yet, but I think that after South Park: The Stick of Truth, Alpha Protocol is Obsidian's best work.

Playing on Windows 8, the last mission became extremely buggy (I would get kicked to the desktop, without a crash, just flipped over, and then have to click back in, then got a hard crash in the helicopter area from nvidia drivers (thanks nvidia)), changing compatibility settings to run in admin mode compatible with windows xp 3 seems to have solved those issues. I didn't have any issues with bugs in the remainder of the game (playing on patch 1.1).

Alpha Protocol is pretty much Obsidian's Mass Effect 2. The game runs on unreal, it has a similar look, has a similar but not entirely the same conversation system, and gives you FAR more latitude to make choices about your character. You recruit allies from unusual sources and engender loyalty through conversations, you gain perks from allies and actions, and use advancement points to build up your character. There are loads of weapons and armor and modifications to those weapons and armor. There are poorly conceived fights with crime bosses who snort cocaine and are nigh invincible. There's hacking, unlocking, tampering with electrical devices, bugging, sneaking, avoiding cameras, unexpected turncoats, a guy who looks like he escaped from Fist of North Star, killing cops, avoiding killing cops, Russian mobsters in track suits, inscrutable paramilitary groups with a mute teen-aged weapons savant, and at least two romance paths (edit, looks like there are four romance paths, I completed two of them in one session, I left one of the options to die in a mission and the other option was a German gun lunatic).

This is pretty much the greatest game EVER, if South Park wasn't so damn good. Way to go Obsidian.