I have both, and am currently going through a bunch of tutorials for rhino, the learning curve is fairly steep, but so far it's incredible. Get Carrara, it's got a great render engine, between carrara and rhino theres nothing you couldn't model. I would get carrara studio now, and buy rhino when you can. Rhino doesn't have a renderer like carrara, but you will get flamingo with it, but it's not as beautiful as carrara's renders.