This game....it's really taken me by surprise. The sheer quality, depth and variety in it is just sublime. Richer than any RPG experience I've played in a good many years, including Oblivion and Mass Effect. In-fact, now I've played Witcher 2, I honestly feel the bar has been raised a good distance. I'll want a lot more from future RPG's in terms of quest variety, customisability and depth.
I also think the visuals are just painfully gorgeous. As in, I can't believe it looks this good sort of beautiful. Ram packed full of intense detail, immense texture work, grandiose scale and some of the best art direction I've seen yet in a game. Usually I dislike LOD pop in/blur, but here it's done so expertly imo it totally adds heaps to the overall look of the game. Essentially mimicking the effects of depth of field. That and the colourful vibrancy, contrast and diversity in palette, it's just all so fantastic.
I'm almost certain Crysis 2 is technically more advanced than Witcher 2, but honestly, I think I may have said wow more times so far from the visuals in W2. Best looking RPG by a landslide, and one of the best looking games yet, period.