while I agree, you were probably seeing more issues with the source that tv when viewing the 7150, that doesn't change the fact the f8500 is the best Samsung tv(in terms of pure picture quality) on the market today.
what I would do, is ensure there's not IR, or physical damage that would bother you on the f8500's. you can check the hours if you want as well. while you're checking for IR, see if there's any dead/stuck pixels at the same time. a quick run through of solid red, green, blue, white slides should do the trick. if all that checks out, but the f8500 and don't look back. I'd still choose it over you options at 3grand. the only competition is oled, and it's still much more expensive per inch.
as for why the TV's were returned, it's a plasma so it could be the dumbest reason you could imagine... seriously though, there's almost no point in even guessing. it could be buzz, it could be IR that they think will be permanent, it could be their cousin who works in IT told them 4k is the new thing and plasma is a dead technology. I've only returned 3 tv in my whole life, and none of them were defective, they were just edgelit led's that had tons of clouding/flashlighting and it took me three tries to realize that was part of their design, not a 'broken' tv... so like I said, ppl return TV's for some dumb reasons, it's hardly worth worrying about what they think they saw. just have a look for yourself, for 1500bux they should at least plug the thing in and let you play some content off a usb for 20mins
Displays: Samsung PN64F8500/JVC X35
AVR: Pioneer VSX-1018AH, 5.1 audio
Sources: HTPC(Mediabrowser), PS3, XBOX360, Wii, Sony DVP-CX995V
Control: Harmony One
Last edited by fierce_gt; 08-24-2014 at 08:23 PM.