I have a Macbook (Intel Core 2 Duo) 2.4ghz with 4 gigs.
I think it's sluggish as well, I'm yet to try it in boot camp, which I've heard you get much better performance. I've heard good things about Fussion, Parallels tech support is horrible. You have to pay to listen to someone from India with a bad attitude, horrible speech impediment on a crackly line at 1/4 volume with no patience. I think it's like $35 per incident right off the bat-1st day our of the box.
However, I had a totally pimped quad-core tower running Vista and the thing scrambled the graphics every hour and you had to reboot it. That was supposed to be my trading computer.
And don't get me started on BB where I bought it and what I went through with them! I LOVE the Mac though, I'll never buy a PC again.