Another thing to consider is that Javs' set up uses a very short throw, so he is at maximum zoom. Never the best choice for optimum sharpness and/or highest contrast, though you do get maximum brightness of course.
This is just another example of how variable screenshot comparisons can be let alone the points Gary raised.
Of course if you want to use them to justify keeping with your existing projector, then it'll help save you money.
I've recently gone from the older X500 model (via a HD350 and X35 before that) and now have an X7500. I mainly bought it for the extra light output as I now have a bigger and lower gain screen than when I bought my X500. I knew that choosing the 7500 I would gain some contrast too as I didn't want to be worse off in that regard after an upgrade, but I've been pleasantly surprised by increased sharpness and better motion (not that I was particularly bothered by it even with my HD350).
I'm feeding my X7500 with upscaled 4k/24p via a Lumagen 2041, so I think this is part of the reason it looks sharper than the X500 did, as it didn't seem to benefit from feeding it 4K, perhaps due to changes in the e-shift from 3 to 4.
I've enjoyed each upgrade from HD350, X35, X500 to X7500 though perhaps the X35 to X500 step was smallest apart from the improved fade to black due to the DI.
FWIW I'm in a long throw set up, so when zoomed back for 16:9 content I'm near the minimum zoom end of the projector and less than half zoom for 2.40:1 content.