I would really like to see how it does with other GPU chips, because it did not do well with the 900 series at all. It was much faster for me to use my own CPU. Of course I do not have an Intel to compare against either, so I'm simply going off the what was at hand.
Aside from the SSS, just looking at the basic benchmark, it's not showing it's value. Of course, I guess we need to setup different Blender benchmarks to clarify this, because right now it doesn't show to be worth it's money. Also with other benchmarks, the 980Ti is showing to be on par, and slightly better than the Titan X, with the industry benchmark tests.
Against the R9 390, it is showing to be better, but not $700 better. I believe the reason we see it as being better in Blender, is that the nVidia kernel is not setup for kernel splitting, like OpenCL. So, in short, it is not fair to compare the two at this time, if that is in fact the case.
Still, I do not see why a Titan would be worth it. The Z was a ploy to get money before the 900 series launch, and both Titans have not shown to be any better than costing more money.
This is my opinion, based on the benchmarks that I have found inside, and outside of the community, from both owners and testers. If I was to find any sort of findings to show that it is better in any way, I would certainly make sure to note it, and possibly have a reason to justify paying the extra money. I'm sorry if this is stepping on anyone's toes, I'm just calling it how I see it.