Neil Blevins shows how OpenSubdiv makes it easier to transfer your models between 3ds Max, Maya, and Mudbox.
WeightPro for 3ds Max
WeightPro is a 3ds Max plugin for automatic, fast and smooth Skin modifier weighting, regardless of mesh topology.
Houdini Engine for Autodesk Maya
SideFX have released Houdini Engine for Maya, with 3ds Max and Unreal versions coming soon.
Reset 3ds Max Windows Script
Raymond Homme Ingebretsen has created a very useful MAXScript that will reset the position of 3ds Max's floating windows.