Personally, eraser tool is the only thing holding me from fully committing to it, the rest is secondary 
Recently I’ve learned that Krita even has a measure tool. That’s cool as I was thinking to tackle a book in a near future that required an angle measurement. Alas, it says here it can’t measure any angle, so it’s kinda situational. But anyway, other programs don’t even have it.
But we diverted from the thread, so let’s end this here.
About the UI, one more story from me. I needed a font manager some time in a past, so I read many reviews of those. But they were bulky and old, so I thought no, this is too bad for me. But then a miracle happened. A brand new program was created. It basic functions were free, it was lightweight, it had a cool modern design, it wasn’t bloat. Well, I thought, that’s it, and just stick with it.