It's on/off contrast will well exceed that of a Kuro. The Kuro, like most plasmas, will have much higher ANSI contrast. Here's what AVForum's Review of the Panasonic ZT65 (aka Panasonic's "Kuro Killer" plasma) had to say:
However blacks aren’t everything of course and we found that when it came to brightness the THX Cinema mode hit 94 cd/m2 and the Professional mode reached 92 cd/m2, whilst the EBU mode was only able to reach 56 cd/m2. We assume that the reason the EBU Default mode is less bright is because it uses studio monitor standards, which tend to place more emphasis on consistency rather than brightness when it comes to luminance. By comparison, the KURO measured at 97 cd/m2, which basically matches the P60ZT65, although the Professional mode could go brighter. We measured the Professional mode at 92 cd/m2 using the Mid Panel Luminance setting but if we used the High setting we could get up to 108 cd/m2. However in this setting the blacks were crushed, which again compromised shadow detail, so we would recommend using the Mid setting. Besides a brightness measurement of 94 cd/m2 is still excellent and with a black level of 0.001 cd/m2 that gives an absolutely incredible on/off contrast ratio of 94,000:1! When it came to the ANSI measurements we found that blacks remained superb, measuring between 0.002 and 0.003 cd/m2, but the brightness did drop off, measuring between 51 and 55 cd/m2. However the resulting ANSI contrast ratio was a superb 20,333:1 and this remarkable dynamic range was easy to see when watching actual content. Interestingly there was a similar drop off in brightness when measuring the ANSI numbers on the KURO and again, as a point of comparison, it produced an on/off contrast ratio of 48,500:1 and an ANSI contrast ratio of 16,676:1. It might have taken Panasonic four years but in the P60ZT65 they have finally produced a plasma that can lay to rest the ghost of KURO.
The X900 can do native on/off contrast on par with the ZT65. With the dynamic iris engaged on any of the three current models (X500, X700, or X900) we get over 350000:1 measured dynamic contrast by an extremely well implemented dynamic iris. The X500, with it's DI enabled can do a black level deeper than the Panasonic 60ZT65 (0.0002918 ftL vs 0.000245 ftL) and has a much brighter peak white (27.43 ftL vs 86.037 ftL). As you can see the dynamic range of the X500 is vastly superior. Now you may say, one is native contrast and the other is dynamic contrast and I agree they are completely different metrics, but as you can see for the peak white level is SO much greater on the X500 that comparing the two without the DI engaged would be silly considering the intended screen size of use for the X500 is much larger. The 60" ZT65 has a screen with a surface area of 11.04166 square feet. If we were to put the JVC on a screen where it matched the ZT65's peak white brightness we can get a better understanding of what a black level for a more practical screen size for the X500 would look like. To get 27.43 peak white foot lamberts from the JVC we'd need a screen size 3.14 times larger or a screen that's 34.7635 square feet. This would bring it's native contrast black level to 0.00091 ftL and it's dynamic contrast black level to .000078371 ftL (factoring in that the X500 has 950 lumens peak white output and ~30000:1 native contrast and 350000:1 dynamic contrast) which is MUCH darker than what the ZT65 and Kuro can do.
So when we put things into perspective, aka putting the two displays at the same peak white brightness and comparing what the contrast and black levels are, the JVCs have a much higher dynamic range with similar native contrast. Overall, once the scene gets dark and the DI actually engages the JVCs will have a noticeable edge PQ wise. There is the argument of higher ANSI contrast on the Kuro/ZT65 so brighter scenes will have a little more "pop" to them, but most will agree that on/off contrast is far more influential in how overall PQ looks. This can be seen by comparing a higher end DLP projector vs a JVC. The same scenario plays out. Brighter scenes have a little more "pop" to them, but the difference in on/off contrast is far more apparent. The Kuro/ZT65 are much better than DLP projectors with on/off contrast so the difference won't be quite as stark, but I still think there will be a noticeable difference in darker scenes between the two. Also you have to factor in the puny size the plasma will be in comparison to the JVCs projected image. I think most would rather go with the JVC at the end of day if they had the room for it.