Far better than a certain Sci-Fi RPG released recently by a company I won't name...
Wait till you get to the ending
They'll have to be compared as series (if comparable at all), so we'll need to wait for The Witcher 3 to come out. They also made some drastic changes to the graphics and game play from the first game, and went with choices not everybody was happy with, so in terms of evolution, they're pretty much running down the same path.
That said The Witcher is indeed a great RPG series. I really like the dark and gritty world they created, by far the most realistic I've ever seen in a medieval fantasy game or movie. Instead of making a fantasy world in which everybody goes along like best chumps, they simply injected magic, mutants and Elder Races in a realistic medieval society.
Some thought Skyrim was a "dark and violent place, torn apart by internal conflicts" but it's just a family theme park compared to Temeria/Pontar Valley's stinky, brutal hell hole.
Va fail !