Short story here:
Walked into my local Best Buy and they actually had an open box 64F8500 on display that obviously had been hanging on the wall at a different store as a demo, as it had massive scratches on the back panel where the remote had once been attached and a check of its hour meter found it to be just under 8000 (!).
Thing is, I walked up to it and it was silent and 100% free of the "sizzle" that caused me to return the new 64F8500 I purchased last December.
Though I love the look of OLED, I love the look of plasma as well and the combination of LG delays and a questionable commitment to flat displays combined to make me pull the trigger and I'll be back in the F8500 camp as of this weekend.
The open box discount was rather significant, and specifically because this unit was gloriously sizzle free, it's worth the gamble to me. Zero burn-in or IR, no obvious loss of brightness, and except for their retina-searing brightness, the PQ of course blew away every LCD display in the Magnolia room.
FWIW, the panel manufacturing date on this set was March 2013, so perhaps some running design change explains the loudness of the sizzle in at least the last round of new sets last year.
At the very least this will tide me over until OLED gets its feet on the ground or dies completely; I just don't want a curved set nor do any of the LCDs on the market now appeal to me, and given the fact that Samsung doesn't have any replacement panels in the parts stream any longer, if it does die I get a refund.
All said, pretty low risk but I'm nevertheless excited.