The new one follows the manga closer, and it also goes farther. I personally prefer it, but I know there are people that like the old one more, and while I think it had good art and animation for it's time, it just didn't age well.....
Go for it. The art is kinda.... eh.... But if you can get past it, it's good. The 2011 anime follows the manga pretty damn closely though. And it has beautiful animation.