No quest problems here, either, though most of the 6 hours or so I played tonight I was free-roaming (got just far enough in the story to reaffirm that I am not a photosensitive epileptic). I'm seeing some minor quirks like my car floating above the sloped pavement, a half-buried NPC, the occasional pile of debris that explode when you step on them and activate the physics, etc., but the only real issue I had was with my performance tanking inside the night club. I think it was an issue with the ray-traced lighting going berserk on some surfaces.
Anyway, the game is great, and fucking beautiful. It's all the shooting and hacking and stealth gameplay of Deus Ex and then some, except you're free to do what you want in a real open world you're almost guaranteed to get lost in, not restricted to passing through tiny levels on the way to your next canned mission. There are loads of side activities, random encounters, and hidden loot to reward exploration, and all your skills improve independently as you use them (up to the governing attribute limit).
It's too soon for me to judge whether choices "matter," but I've definitely seen several that seem like they could so far. Tons of creative solutions to problems and bonus dialog options based on your attribute levels and background knowledge (character origin story), too. I'm wondering if there's a level cap, though, 'cause every level-up gives you another attribute point to spend and it seems like it'd be too convenient if you could max out all of them.