I just asked Eovia on the phone. They sold Carrara 3 as a sidegrade to Poser, but not Carrara 4. You can buy it as an upgrade from Carrara 2 or 3 for $189 as a download or $199 via UPS. Isn't Carrara 2 out there for free in a magazine? I don't remember for sure. Carrara 4 Pro comes with Amapi Designer 7 which is a serious modeling app. It also has it's own Carrara modeler, so it has two modeling packages, really. That made a big difference to me, but you may not care about that. XSI is interesting, but no Poser animation import. Personally, I didn't care for the demo. I can work faster in Carrara, but that's highly subjective. Not sure about workflow with Amapi 7 since I haven't tried it yet.