The game is Great and it has a lot of replay value. You dont really need to play the original to enjoy the Sequel.
-One of the best looking Game of 2011
-High replay value because of multiple paths and multiple endings
-Story that is player driven. You get to choose what to do in certain scenarios and situations.
Do you side with the ruling party thats trying to preserve peace in whatever means nescessary or with a group of rebels thats just fighting for their freedom and equal rights?
Do you kill an enemy thats already defeated or let him live cause he might be usefull in the future?
Those sorts of choices that forms different branches of the story and leads to different endings.
-Unlike Mass Effect that when you choose an option, you get results immediately. The results of your choices in Witcher 2 will not be seen immedaitely. It could affect later on the game or in the middle of your journey so you cant do the save 1st then select, if you dont like the results - reload.
-Great Sounds, great atmosphere, very engaging, interesting characters
This game is really worth it..