That depends on what you want to use it for.
The permedia2 is good for 2D but if 3D gaming is important to you, a voodoo 3 or voodoo 5 may be a better choice.
The permedia doesn't have a full 3D feature set, so you'll get monochrome lighting in games like quake 2, little things like that. Also, most voodoo cards come equipped with more memory than the 8Mb of the CVisionPPC.
On the software front, for the time being you'll have to stick to CyberGfx.
I have a BVision and ame happy enough with it and haven't noticed any huge incompatibilites - I'd expect a CVision to be the same...
There are benefits to a PCI expansion aside from gfx cards, but you do seem to be well kitted out for expansons already.
