The only problem I find with MoI is the lack of variable radius filleting. Michael says he is working on it, so we will have it eventually.

As for filleting success, it often depends on the underlying engine. Autodesk have developed there own having broken away from the standard ACIS kernel when Spatial were acquired by Dassault (owner of Solidworks and a Parasolid engine user).

You can get Inventor Fusion for free at the moment. Often it's filleting engine will succeed where MoI's fails particularly where edges join at acute angles.