Firstly, I got the game yesterday, which I was surprised about as I normally get games one day early on thursdays via the post (In the UK here). In any case, with the other parts of the forum not being open yet, it's alright to post this here I assume?
Regardless, I'm about 3 - 4 hours in by my guess on the PS3. No bugs or technical issues, though I have noticed that after opening a menu and closing it, your character can be a bit reluctant to move for like a second or two. That is the only minor issue I have and it is indeed very minor. So, from someone who never had problems with Alpha Protocol but did with Fallout: New Vegas on the technical front (enjoyed both, but did stop New Vegas due to the technical issues a week or two after release), I reckon Obsidian have done a great job here. I don't know whether it's down to using their own engine or due to extra testing, but it doesn't matter.
Now, I'm about to go searching for a key to the Causeway. I'm not sure if that means I'm about to enter the second major area of the game but I'm assuming I'm still in the first act/big area as I've yet to complete the first over-arching goal. The game controls well in my mind and I'm playing as Lucas. I've got my first companion, Anjali, and her AI is competent. However, I did note on the boss fight I ran into in the Gunderic quest, that she was a bit reluctant to ressurect me at times. As I'm playing on hardcore, it lead to quite a few reloads. Still, the AI does hold its own and I like the synergy between the skills and how if Anjali uses her fire aura ability, you can move into it and heal. As I'm playing as Lucas, it's quite useful. Also, on hardcore difficulty, you really do need to make use of block and dodge to good effect. I found the enemy casters quite challenging as well. Overall, I find the combat fun.
On the writing and story front (and keep in mind I'm a writer myself, though not for games), I find it to be up to Obsidian's usual standards. Gunderic's Manor being the highlight so far, with the lore entries and such. The story itself hasn't really got going yet though. In addition, I think I just encountered my first instance of choice and consequence, because I had to make a choice during the Gunderic quest. I was told what I did could have consequences later by Anjali. Obviously, I cannot verify what may happen later due to what I did, but I think it does highlight that the game does have choice and consequence even if it's not as fully fleshed out as in something like Alpha Protocol (I really enjoyed the choice and consequence system there).
Now, my issues? Keep in mind that I could care less about co-op. I play games for the story and singleplayer, though I do hop online in games such as FPS' and Little Big Planet on odd occasions. So, I'm not going to comment on that but I do want to note that while there is plenty of loot be found, I've not found one piece of different looking armor yet. I know this is because the items all have the same name so far, such as 'tassets of' or 'hauberk of' and that there'll be different armor appearances later as I get further in the game (I'm level 6 or 7 at the moment I think), I thought it was worth mentioning. Weapons have changed though and shields may have, but I've not paid much attention to that. So really, as one of the joys of hack and slash games (for me anyway) is getting better gear and seeing your character evolve appearance wise is one of the joys, I thought I'd mention that. While I'm mentioning loot as well, the loot is colour coded for those who've not played the demo. I've ran into white, green and blue so far. I hear there's a gold or orange rarity above them (I've seen one in the shops though). Also, characters can only equip items of a certain type, but you won't have to worry about searching through items your character can't equip as they don't appear when equipping the character.
Also, for people wondering, I have played Dungeon Siege 1 and Dungeon Siege 2. I never played them much however, but that's not because I didn't enjoy them. I did and found the second game to be better as you could go back and farm enemies (that reminds me, enemies do respawn in this game but chests don't seem to, alongside bosses). For people complaining about the game, the game does have what's important in a Dungeon Siege game, which is the loot (minus what I mentioned about a lack of appearance changing items so far armor wise). In other areas, it's best to class the game as something else if you're a stickler for the game being what is essentially a carbon copy of the previous games with added features. In other words, treat it as a different game but one that's set in the same world as the previous titles. If you can divorce yourself from thinking about it's different from previous titles, then you should enjoy the game as it's solid in my view. Not absolutely amazing, but solid for what it is. Keep in mind that this may not apply to PC gamers though (due to possible control issues) as I've not tried the demo on the PC due to my PC essentially being out of commission right now.
Hope this helps and I may back to answer questions later. Feel free to post your impressions as well.
Edit: I forgot to mention that when browsing items and equipping, it clearly shows what statistics are being lowered and raised. However, there are no tooltips explaining what the statistics do. Instead, you'll need to press start and view the help topics. Also, the statistic system employed is essentially the same as those employed by MMORPGS. So, if you have 5 armor and it mitigates 30% of the damage you receive at level 1, you'll find that if your armor rating is still 5 at level 4, your armor will mitigate something like 10 - 15%. That reminds me as well, if any Obsidian dev sees this, it might be worth implementing a feature where we can see how much damage our current armor rating allows us to absorb.