Being a VMware Fusion user I pondered about the new Parallels Desktop 4 -out now-, I have downloaded the trial, requested the key and wow, it is much faster than VMware Fusion 2.
Only downside, silly to say the least, the icons that used to be at the right margin and have moved to the top side of the window, like Fusion does, got a fugly look and it seems there is only one set of them. Setting icon size as small kind of mitigates it…
So, if you thought VMware Fusion was fast enough (to me it was), give Parallels Desktop 4 a try. Rest assured you would be pleasingly surprised.