My thoughts:
I play it on minimum settings, in 800x600, on my laptop with ATI Radeon 545V, Pentium T4500, 2,3 GHz, 4 GB RAM. I don't know how many FPS it achieves, but its enough to not stutter. Only problems I have with ui is too small font.
I'm near the end of the 1st chapter.
Story is great, dialogs are wastly superior to the first part, quests are original and interesting, and I didn't have one fed-ex, or kill X monsters of type Y quests so far. Some quests involved moving things between places, but it felt natural, and didn't required much backtracing the same path over and over.
Mechanic for fighting and dialogues definitely is there - there is even option to show small window in the bottom right corner of the screen, where you can see rolls of dices, and which skill was activated with what result. Still, fighting is heavily reflex based.
There are dialogue skills, "jedi mind trick" is my favorite. Dialogue skills, and some other develops thorught use, not by leveling up.
Leveling up only allows player to assign points into skills like fighting, alchemy or magic.
Crafting is easier than in TW1, and ingredients are abound (but maybe it's because of the place the 1st chapter is going on in). Much more things to craft, bombs and traps really matter this time. Alchemy feels slightly less important (because potions are only allowed before fight, so it's inconvenient). Still, some fights are almost impossible without alchemy (or maybe it's my poor reflex).
You probably want to turn off difficult QTEs in the options. QTEs is the biggest fail of TW2 IMHO. Timed dialogs are not so bad, because there's not many of them. I've seen it 2 times so far, and it made sense for both to be timed.
Fist fighting is actually worse than in TW1 - it's QTE ffs.
Stealth is completely optional, but not as badly implemented, as I thought it will be. Still - fells like another minigame.
C&C - better executed than in the first (at least these, that I've seen so far). Also - they really made many, many quests you won't find in the first playthrought. I'm watching Toegoff LPs of this game (with some delay, so I won't spoil my game, and althought main choices we made the same, games are still different, because of minor details, that really matters.
Overall I'm really enjoying this, mainly because of story, atmosphere, and fighting (in this order). Fighting is consolish, but damn, it's rewarding (because it's fair and not too easy - most errors will kill you).
9/10 (but I'm biased potato).
Story of this game has some spoilers for Sapkowski books, that weren't released in English yet. Not too big spoilers, but still.