I think that if I had to choose White Wolf's system over the d20 system, I would probably go with the d20 system just because its more in-depth. But that is just the way I am.
White Wolf's d10 system is simple and easy to use, so it is just as good. Vampire, I beleive, is the best game out of all of the Worlds of Darkness. I have played Changeling, Vampire, Hunter, Werewolf, and Demon. Werewolf and Demon are tied for second place. Demon is new, but still pretty cool. Hopefully more books will come out and expand it a bit more. Hunter wasnt very good at all. But, White Wolf makes another game called Demon Hunter X, which is very good. Its not in the Worlds of Darkness, though.
It was always fun, although the Game Master we had was a lamer all the time and he used to change the rules to how he wanted them and such. We got rid of his dumb ass the past few times we played and it was still just as fun.
...God I hate that kid...