I haven't used Photoshop; learned basic photo editing in GIMP (as a poor student, I appreciated a powerful, free editor). So, no complaints about the UI from me. If anything, I'd probably bitch about the Photoshop UI if I ever used it.

One thing that concerns me a little, however, is the third-party integration with Nik Collection. The second version, which I'm still using, was provided for free by Google. They later sold the software, and the new company commercialized it. I found it difficult to track down the v2 installer, so I'm now keeping it on multiple backups, in multiple locations, as one of my most treasured software possessions.