As a big fan of the games and of course the books, I spent the night watching the whole season. While it is a little slow at times, for Witcher fans it is wonderful to watch. The biggest problem viewers that do not know the books or the games lies in the fact that the plot jumps around between past and present, and unfortunately it doesn't show that with any type of hint. However, once even a viewer new to the series gets to episode four, it should become pretty clear.
Henry Cavell's performance was outstanding. The voice was perfect, the required stoicism clearly showed. I am always a little leery of TV adaptions, but Netflix nailed it.
I have to say I am extremely happy with the adaptation of my favorite games of all times.