The F5 actually does the G lenses. Did most of my test roll with a G lens. I think you hit the main points correctly......unless you want to play with older lens and/or you want the pro build, the F100 is a wonderful camera only out done by the F6 which is still much more expensive than most of us want to spend.
After playing with the F5, I must say I am extremely satisified with my purchase. This was the perfect upgrade to my F4S.
Perhaps another reason some folks prefer the F5 is that it is a good transition between the all knob operated F4 and the completely menu driven F6 and I believe that the F100 is heavily menu driven too.
The other thing that has kept me from the F100 is/was all the plastic stuff that broke or had to be sent in to get fixed. I believe on the early ones, there was a big problem with the plastic film rewind fork. I just didn't want to deal with that or it potential.