Witcher 3 is much, much better than the first game. The game engine and gameplay are extremely clunky in the first game. I have started it a couple of times and quit out within a few hours each time. I would highly recommend Witcher 3 though, have finished it twice.i never got past the first screen of the first game. that dragon fire thing.
As for the TV episodes, havent watched any of them yet, but I just cannot imagine Henry Cavill as the Witcher. He has been horrible in every movie I have watched him in.