I'm actually going to be doing the opposite. I'm going to BB today to return my 60F8500 and try out the 60ST60.
The F8500 has the best PQ I've seen so far, isn't reflective at all, gets plenty bright in sunlight, has an awesome remote, awesome smart suite, and gets rid of IR super fast. There are 2 reasons why I'm returning it: buzzing and eye fatigue. When I sit centered with the TV about 10-11ft back, the buzzing is pretty annoying even at moderate listening volumes. I can hear the buzzing and the audio at the same time, the buzzing is such a distinct pitch. If the buzzing is equal on the ST60, I still might keep it knowing I saved $1400. The eye fatigue is what really gets me. When I watch blu-rays in the dark, my eyes feel like they are straining to concentrate on the action, and I can feel them get squintier and squintier. After a while I realize I have no idea what is happening in the movie because all my attention has been directed on how fatigued my eyes get. I've never had this problem on LCDs, so maybe I just can't handle plasma flicker or whatever, I guess time will tell when my ST60 gets here...
edit: I might actually try the VT60 since it isn't as bright as the ST60 and has better 3D.
Sorry if this post doesn't help you lol
Office - Onkyo 506, AV123 X-LS Encore Monitors
Living Room - Panasonic 60ST60, Onkyo 707, Ascend Acoustics Sierra-1 LCR
Car - Focal Flax 3-ways; Arc Audio KS 2500.1, 300.4, 300.2; Audison BitOne; Illusion Audio C12 XL