Best feature: price. Hate to admit it, but that is the "real" reason I went with Carrara. Of course I got a side/upgrade from RayDream, but it was still the price first of all.... I stayed with Carrara because the interface is easy to learn, and also because each generation has seen steady advances in renderspeed, stability, and features. I always thought I'd move on to a "bigger" program, but now that there are several developers making plug-ins (4 is better than 2), and some really "pro" features have been added (render nodes, pro importer, real skies), It's a challenge for to keep up.