I am about to invest in a modeling program, and almost made up my mind. Formz seems to be the best for my needs, but I don't like the renderer that much. I think you'd find that with practice and experience you can get Z to do what you need. Also, it is important to note that workflow gets really bungled up when swapping between multiple apps - this can be a real time killer.
Cinema seems to be a really nice package.
I personally like Lightwave a good bit, but from what I hear it isn't running so well on Macs these days. Hope that helps. They will be a render hit but not as much as a complete radiosity. This is similar in any renderer, and from what I know there isn't any other program that gets this effect simply with shadow mapping. There is plenty you can do with it, including soft shadows.