Photoshop has a nice looking UI but there are some very subtle but really useful things GIMP does that Photoshop doesn't. For example when drawing with the Rectangle/Ellipse tool GIMP doesn't immediately lock in the selection but gives me handles I can use to perfectly fine tune the selection down to the pixel, especially for the ellipse tool. I don't get that level of control over the marquee tool in Photoshop.
I can also freely scroll and zoom while using the lasso tool in GIMP and it can go between free draw lasso and poly draw lasso by clicking and dragging or just clicking to establish new lasso nodes. And I can just undo any of those nodes by hitting backspace.
The only tool I really miss in GIMP is the magnetic lasso but needing to drag the cursor all the way to the edge of the screen just to scroll somewhere else on an image makes the tool so much worse.
I have both gimp and Photoshop and for the grand majority of things that I need to do minor photo editing, gimp is my preferred choice.
Sure, the interface is simplistic, but it works really well once you learn how to make it work, at least for my specific needs.
I will follow that up by saying that I am not a graphic designer and nothing that I make is published to the public, but despite that I actually enjoy using gimp.
I used Joplin everyday for half a year but switched to Obsidian after that. They both essentially do the same, but I found the latter to be more adaptable to my needs and paradoxically easier to modify.
Don't get me wrong, the open source one in still great. Served me well while I was using it.
MasterCAM blows absolutely every open-source solution out of the water. It isn't even a competition. In this case, it is actually cheaper to buy their really expensive and restrictive license, because in the end you save a near immeasurable amount of time in modeling, drafting, programming, and production. The fee CAD programs that can even support a postprocessing operation (becoming closer to a real CAM solution) are really bad at it and the toolpaths are far from ideal.