I don't have an iPhone/iPod, but have VF and the VV series on my PC. I think the main differences are that the computer versions can have more people than the iPhone/iPod versions because of the more memory available. I think the maximum in VV2 iPhone/iPod is 40, whereas in the Windows/Mac PC versions it's 90, with the possibility of more in some cases. In VF iPhone/iPod I think the maximum number of kids in a family is four whereas the maximum is six in Windows/Mac.

The version of VV1 for iPhone/iPod wasn't developed by LDW, and the graphics in particular look completely different. I can't speak about the gameplay. VV1 Mac/Windows graphics look much more like those in VV2.

LDW haven't announced if or when they'll be porting VV3 to the iPhone/iPod platform, so you'll have to wait several months at least. I'd definitely recommend getting all the LDW games on PCs if you can!