Answer by Thomas Zerbarini:
Of course the worst characteristic of a T-Tail is the onset of a "T-Tail deep stall."
An advantage to high wing aircraft also includes raising the wing higher off the ground for large aircraft and/or aircraft that may operate on unimproved fields. These aircraft include the C-5, C-17, C141, C130 etc…
The high wing on large aircraft allows engine clearance even as the wings droop with the enormous weight when they are operating on the ground. In addition, the high wing keeps the engines higher off the surface to minimize the ingestion of foreign material that can damage the engine.
There are also aircraft that have high wings and "top mounted" engines. Check this C-17 test aircraft:
I believe this prototype YC-14 is still in the Pima Air Museum in Tucson AZ.