For me, after a few patches to Vue 4, it ran very stable except it had serious speed issues in OpenGL, which I never used because of that.

When I bought Vue Pro, it was very unstable (and really unusable on my machine). After a couple of patches, I've gone back to try it again and I will have to admit it's been a bit more stable and usable. It still does have some sort of resource memory leak on my computer which shows up after an hour or two in which the menus in windows start to disappear and do all sorts of weird things. I never had this problem in Vue 4, which I could use for hours. I haven't been able to track th leak, but it seems to have to do with the material editor. When it goes into that crazy mode, it is still usable (unlike originally where it would just crash and burn), but the material editor does slow down quite a bit.

Still, I am starting now finally after months of craziness, to see the light at the end of the tunnel and the potential that Vue Pro has. I don't think it's quite done yet, but it's getting there. Got a chance to use the Poser changed reload feature which is awesome for what I do.

ShadowWind

I have a:
P4-1.8
512 Meg of RAM
All-In-Wonder 9700 Pro (what catalyst drivers are you running Gebe?)
Vue Pro is on it's own 30 gig drive.