I have an 07' YFZ450 ... I'm not very good at riding it, but it just feels too small for me.
I haven't ever ridden a Raptor in comparison however.
Personally, I wish I would have gone with the Raptor primarily because it's fuel injected and I could have taken it up in the mountains and ridden it without hassle ... that and it seems like it might have been a better choice for a taller heavier person.
The YFZ seems to me like without a lot of work done to the suspension it's primarily built for MX tracks, and that's about it.
I only have limited seat time on mine in the sand, but it's definatley more fun in the sand than it is in the dirt....wheras, it seems to me like a dirt bike would be an awful lot more fun in the dirt...
I dunno, as I said before, I'm not a very experienced dirt rider at all, but that's been my impression hence far.