The double-length keys for bk/delete/enter/space allows a lot of vertical travel freedom on the hand. Instead of flexing the fingers I can just move the whole hand down and hit the lower row _very_ comfortably while not having to worry about the thumb at all.
I've mocked a few pieces of paper to advantage with the shape of the glove80 cluster and I really can't decide if that's good or bad. While the inner thumb keys of the advantage are pretty far from the key wells, the most important modifiers are all closer compared to the glove80.
Trying it on the mockup, the glove80 cluster placement forces my hand on a higher position and requires the thumb to stretch more.
I've been looking at the advantage 360 and I don't like the complete removal of the Fn row, while at the same time I also hate the old Fn keys on the advantage. The glove80 layout is really nice, but I find the thumb cluster of the advantage to be pretty darn good.