I never played the first one, am I missing out? I've seen all the trailers there are to see for Witcher 2 and I am amazed, I definitely plan on getting this game.
I would say so. Get the Enhanced Edition. At the very first, as in the first 20 mins of the tutorial, the game will seem kind of "eh." At least it did to me. The writing seems kind of hackneyed and all you've got is the combat system, which, on an enemy by enemy basis, isn't that great.
Once the tutorial gets under way though, the game really speeds up. The story improves once it gets away from the main plot somewhat as well. The chapters are long. Areas are huge. There are lots of quests and multiple ways for each quest to play out. A lot of choices as you deal with NPCs or quests can have long-reaching repercussions. The leveling system and the item and alchemy system is quite meaty. Combat turns out to be more fun when all your moves are rolled out, and they throw lots of enemies at you.
I'm probably 65% to 70% through the game, and I put it down for a while, because I had been playing it for quite a long time. Still meaning to finish it, rather than a lot of games I just uninstall at this point.
So yeah, give it a whirl.