Black level performance
I describe both projectors as ultra high contrast 3LCD projectors, and as such, they have the latest in 3LCD panels, and polarization techniques. The end result is black level performance superior to the more typical 3LCD and DLP projectors out there. Still the 8500UB is a year newer, and has a further improved iris and some tweaks to the polarization, to make it's black levels still better than before, and they were already a bit better than the Sanyo projector.
For your consideration of black level performance, below you will find several side by side images of the two projectors in action. These are 6500UB vs. PLV-Z3000 images, not the 8500UB!!!
I haven't seen a Z3000 here in over a year and a half, so no chance to shoot it side-by-side with any of the newer projectors.
Keep in mind, that because the Epson is significantly brighter in "best" mode than the Sanyo, the Epson images below are brighter. You can see that eaily in the first image - the light blue Legendary Pictures logo appears more overexposed on the left (Epson), and you can also see it in how blurred (by overexposure) the pause symbol in the lower left corner is on the Epson. Even so, the background on the Epson image is still not quite as bright as the Sanyo.
Note: Don't worry about color shifts - at these long exposures (typically 10+ seconds) subtle differences in color are greatly exaggerated. For all side-by-side images, the Epson is on the left.
In the city night image above from The Dark Knight, you can again see that the Epson is brighter. Try to take that into consideration, then compare some of the dark rooftops in the frame. Despite the Epson being brighter (look at the lights in any building), the dark rooftops are still blacker with the Epson.
Unlike the two images above, the starship image (below) from The Fifth Element, was taken during a different photo shoot, and the PLV-Z3000 is on the left, this time.
Bottom line: The PLV-Z3000 has rather excellent black levels, certainly the best at its price or below, but the Epson is definitely noticeably better. We're not talking a huge difference, but big enough to make the difference in black level performance a serious consideration in your final decision between these two. Remember it's the scenes that are pretty much dark overall, with no really bright areas, where the black level difference is most important. The overexposed Starship image above is a great example.