Installed this last night and played a couple of hours. Very impressed with the world and its detail and the gritty portrayal of life it produces. I like the lore of The Witcher too and as expected the characters and quests are really well fleshed-out.
There are some things stopping me getting quite a immersed as I might, though. First is the clunky feel of movement and combat. Every time Geralt starts off moving or changes dirsction it feels juddery in a way I'm not used to having become accustomed to g-sync. I'm not 100% convinced g-sync is actually working. Also I've lost count of the number of times I've ended up running him into walls, fences, doorways, etc. It quite breaks the immersion when my grizzled witcher seems unable to navigate a simple wooden walkway...
I'm finding the combat a bit cumbersome too. Having come straight from Shadows of Mordor, it feels very slow and clumsy controlling Geralt in fights. Also I suck at it, it seems
Despite the issues, the world, the lore and the detail will keep pulling me back in, I'm sure.