

Exhibit A: the text tool.
In general though, I find the UX to just be worse across the board. Too many steps. Non-intuitive defaults. Bad keyboard shortcuts. and so on.
To be honest, I have successfully avoided using bare GIMP for enough years now (not sure how old PhotoGIMP is, but I think it’s been around at least 5 years) that the specific bad memories are fading.
I do think GIMP has objectively bad UX in the sense that it’s definitely not just “I was used to Photoshop first so I automatically think everything else sucks.” Probably the last ~20 years of flamewars started by people pissing off the devs by saying the exact same thing is some evidence of that. But I’m not a UX expert and haven’t sat down to do a side-by-side comparison… honestly, that’s something I’d really enjoy reading/watching if somebody did do it.
If such a thing existed, it’d be coolest if they did it with one of the “good” versions of classic Photoshop, like version 7 or whatever was made by pirates into a portable app in the 2000s. I have no idea how far the UX has evolved in Adobe’s rent-seeking era because I stopped using even portable Photoshop when I switched to Linux as my daily driver for good in 2015 or so. Then suffered with GIMP for a few years, hating every nanosecond of it, til PhotoGIMP came along.
There’s even an unofficial AppImage of it now, which is nice because the one that deals with the Flatpak seems to break every time the Flatpak gets updated.