I watched the first ep, and enjoyed it overall. Pretty gory but the visuals weren't super well done in that department. I agree that it seems like a strong cast, with a few exceptions I think. Maybe it just seems that way because Bean can eat a scene right around you. A nice start that made me want to tune into the next episode.
I've never read the books, is there that much sex in those too? Or is it just HBO being HBO?