Yes, complex editing operations on polysurfaces imported from MoI/Rhino to SpaceClaim using 3dm file format are possible. However, when I used to edit (e.g. did shelling) "free-form" kind of objects rather than mechanical one I usually ended up with invalid object when checking in Rhino.
I also disliked a concept of "active command" and user interface that puts big and small button icons together - it isn't clearly arranged.
But for changing a fillets, moving a face or other "simple" editing operations it was very very handy...