I run Parallels and it works really well for me.
I typically run software development environments (Eclipse, NetBeans) which are quite memory intensive, but work well.
I'd recommend downloading the trials of both and seeing which you prefer.
Sorry to drift OT a bit, but why do you run Eclipse and NetBeans in a VM - you can run both of them natively in OSX...
Back on topic again, I have bought Fusion and Parallels (I got Parallels before Fusion cam out) and much prefer Fusion