I saw my 2nd ZT60 at another MHT location, giving me a chance to compare them with the F8500s located on the same wall.
To start, I noticed an issue with both of the ZT60s at both locations, a vertical line down the right side of the picture. The line tended to be darker than the surrounding area and appeared to be about 1" or so wide. On the first ZT60, due to the dark scene from Skyfall that was being repeated at the first MHT location, the line wasn't too bad, but still visible. However at the 2nd location, where the MHT store manager does a great job of setting up these panels (certainly better than the average MHT location), the vertical line was much more visible. At this location they were playing an HD nature video and there was a mix of bright daytime scenes together with some darker scenes. In the brighter scenes, you couldn't help but notice the line and its visibility varied depending on the color of the background. No other panel showed this and they were all playing the same material.
Now either this is inherent in the ZT60 or BB has gotten a bad shipment of ZT60s.
However with that said, the comparison of the ZT60 & F8500 was pretty much on par with that of the VT60 & F8500. The daytime scenes were really dramatic, IMO, in that the F8500 had much more depth and looked far more as you'd expect an outdoor scene to look. The ZT60 simply did not have the contrast to show these bright scenes like the F8500 could. At times it was dramatic.
I tried changing the mode to THX Bright Room. Basically that brightened the picture, but also flattened it out in a sense. So the picture was brighter, but the apparent contrast seemed even less. Regardless of settings, I could clearly make out more detail in the F8500.
All things considered, I'm glad I chose the 8500!