Tonight (yes, I am working on a Friday night), I ran into a new issue that I thought the community might be interested in. I linked an IFC into Revit which was exported from AutoCAD MEP.
The issue is, I could not see any of the duct.
Autodesk posted a solution to the problem that unfortunately did not work for me. After a little experimenting, I discovered that if you switch to a reflected ceiling plan view, the duct work from the IFC was visible in my view.
Hope this helps somebody someday!