Recently purchased Izo 4....very happy camper, lovely interface(s), and a learning curve of 1......unless you dig into the variables. Also got Izo Nectar for vox. Again, very cool, loving the stuttering effect you can achieve with the pitch interface. Just starting with it, and thoroughly enjoying!
Interestingly, I downloaded a demo of the Sony CD architect s/w, and I really was dissapointed by it's interface. I'm sure the results would be fine though.
Just my penny's worth.