To help yourself decide, take a look at apps written with various frameworks (screenshots or preferably live) and judge their look and feel.
I've done quite a bit of GUI-framework stuff in the past, and I've found that * It's not hard to write a crappy framework for one platform. * It's a lot harder to give it a decent appearance and user experience. * It's nearly impossible to make one that does the above on multiple platforms. In fact I don't know of any really good cross-platform GUI framework. Qt, Tk, Swing, etc. apps are garbage. These days people seem to just give up and write web apps and wrap a 200MB Electron wrapper around them and call that a "native" app. (But bear in mind that I'm an Apple developer, and ex-Apple engineer, so my standards are super high. 2 ½ of my years at Apple were spent tech-leading the AWT peer implementation, trying to make Java apps work well on Mac OS and failing, so I've got some skin in this game.)
