Do you receive drawings from an Architect that uses Revit Architecture? Or does your company produce drawings in Revit Architecture?
My opinion is that if you receive models from an Architect using Revit Architecture then go Revit MEP. If you get drawings that are 2D flat dumb objects all though you can use Revit MEP, your best bet would be to stay in a 2D environment and fo AutoCAD MEP.
Some people may beg to differ with me, because AutoCAD MEP does produce in 3D however not the way Revit does. If you use AutoCAD and your clients do presently then use AutoCAD MEP.
hope this helps, and some others can elaborate on this if they like.