Having dabbled in both Carrara and Vue, I think Vue is a much better value for about the same price. Though you'll instantly find a compatible GUI in Carrara (trackball, etc.), the render engine is dreadful and slow. And forget adding more than a few figures without a major slowdown or even crash. I was working with c5 or 6 I believe.

Vue's viewport setup is a bit wanky but makes better pictures and has an easier IBL system, more user-friendly texture mapping system and seems to handle Poser import with more stability.

All of this is just opinion, mind you...:)