Well, actually Carrara's rooms are no different from tabbed separation of features. Come to think of it, they are actually tabs but just designed differently. And I realized I'm wrong in a way. Looking at Modo's UI, it's efficiently organized with palettes and tabs comparable to rooms. But don't get me wrong. Right now, Modo is unbeatable, imo. I was very impressed when I saw a preview of a shoe modeling tut. That was awesome!