I've recently tried GIMP after reading about an update on Hacker News (not this one) and it was an absolute disaster - took forever to start, nothing worked, UI was glitchy, and then I accidentally quit it because I didn't know what the empty, floating window was good for.

It's a pity that Gtk apps usually don't really work on macOS, it makes it much more unlikely for us Apple users to contribute on GitHub etc. :( I'd much prefer a native cross-platform toolkit to the web-based stuff that's popular now.