Two episodes in and it's falling short of my already modest expectations. I feel like I'm in a strange position with my motivation to continue watching it; if I hadn't read any of the books or played any of the games, I'd have dropped it after the first episode, but having experienced some of the other media, I find the show really isn't holding up in comparison.
Standing on it's own I think it would be nearly unwatchable. So far there are a bunch of non-characters and a lot of clumsy exposition that does far more telling who these character are supposed to be than showing who they are, most especially in the case of Geralt himself. I'm not liking Cavil as Geralt and some of the other casting choices don't seem to be fitting well either. I liked the Queen they killed off (of course) in the first episode, and they seem to be doing a decent job with Yennifer, so far. But most of the rest is just blandness, interspersed with an exaggerated gravelly voiced Geralt, and an obnoxiously anachronistic Dandelion.
The CG is mediocre, the sets are pretty bad, while pacing and continuity are a muddled. Fight choreography isn't terrible compared to, say, Iron Fist or Game of Thrones, it but could have been a lot better. Distinct lack of atmosphere as well, which is something the games and books had in abundance.
As has been mentioned, it feels like they took the Witcher cliff notes and are trying to give it the Game of Thrones treatment. I'll probably finish it, but at this point I'm not expecting much.
Maybe I'll go back and watch the old Polish Hexer series...I don't think it could possibly be worse, despite the comparatively non-existent production values/budget.