Oh indeed.
I am re-watching all the discs I have with Atmos and Dts:X again...
So far standout Atmos have been the Ready Player One, The Great Wall and Rampage
For Dts:X Fast and Furious 8 and Crimson Peak is turning out nice too.
There are currently a lot more Atmos than Dts :X and the number in the UK is probably less than else where. Some should be, but these are either just the True HD or Dts MA variants. This of course it is only for Blu-rays. I think most of the UHD discs have one or other but I don't have any of those currently.
Depending upon what you plan for either the Heights, Overheads or the Atmos Bounce you may notice the effects to be more or less effective. I have gone with Heights out necessity so some things I don't think improve over previous the 7.1 might be down to this and Overhead might work better.
Good Dts MA and True HD still sound good whether the upmixer is bringing anything noticeable to the table or not.