It's definitely slower than MoI but it has loads more bloat too - You can handle much larger files in Rhino so you may well find you will need both.

MoI as intended for speedy concept drawing.

Rhino for adding the detailing.

I recently worked with Angelo Simeonidis on his Majestic 1 frankenstein bot. It needed cleaning up for render and the only tool I could was Rhino. When the model first arrived here it was 1.3Gb in size :) And even after stripping out all the render mesh data it was still over 630mb.

So the new Rhino for Mac has it's place, but it's certainly not a MoI replacement

Martin
(TpwUK)