I own and use both MoI and Rhino. I always start a project in MoI and keep it there as much as possible, but there are often things that I cannot do in MoI because some tools are sometimes not there yet, but the main reason to go the Rhino is to be able to use the analysis tools (zebra, environment map etc.) that are essential for me to ensure smoothness and continuity. Also I have Flamingo as an add-on relatively rudimentary renderer. The beauty of this combination is that I can simply copy and paste back and forth between MoI and Rhino. Also, for complex projects, I find it much easier to store parts of a model in Rhino layers, as I have never quite grasped the equivalent feature in MoI.

So the bottom line for me is that MoI and Rhino/Flamingo (and Penguin) work best as a team, but I have to admit that it is a bit of a luxury. However, I could not justify upgrading to Rhino 4.0 and I have to make myself happy with good old 3.0. The only thing I am missing, I feel, is the cage deformer feature, which might come handy in some of the weird things I do with aircraft and ship hulls. The other thing is that Brazil looks like a great rendering software, but it works only with 4.0. But for high-end rendering, I own Modo, to which MoI exports beautifully, but I have not quite mastered yet (and that is an understatement) the very complex user interface of a high end renderer like Modo.

As you can see, I have never been too good at choosing. If only polygamy was not illegal …