Fantastic write up rmcc.
To the OP, I can't answer your question directly, but everything you have heard is true. It will over heat if you don't take some care, it will not load maps if you don't have the right app etc. etc. Everything on the bright side is true also. If I had to choose between the two I think it would be the phone. It's a Swiss Army Knife as rmcc so elegantly explained. YOU DON'T HAVE TO RELY ON JUST ONE APP. I ran this get up on the center third of the TAT two months ago.
I'm not ready to leave the GPS at home, but I don't figure that time is far off. The phone served as a SPOT substitute also.