By personal experience, wxWindows is "OK", but it's not a panacea. There are a ton of little quirks that will burn you when doing cross-platform development simply because native controls do not behave in the same way. HiDpi is a major pain with wxWindows (but then again, the way HiDpi is managed is a pain irrespective of the toolkit).

But if you do some forms and basic UI controls, wxWindows does the job egregiously. Looks the way it should be on all platforms.

It's funny an article from 2016 mentions issues about text rendering, because certainly we've been regressing in this area. I can spot QML and Electron apps by the broken text rendering alone. FF60+ with quantum has incorrect subpixel hinting and does not correctly hint at all sometimes.

Many of the mentioned apps int the article are "broken" in my eyes: I don't have perfect vision, and I do expect apps to follow the system text scaling (and they don't). For a "broken by design" example, see Darktable, which is awesome, and should do this by default, but the authors hard-coded a theme where literally every widget is styled for looks and not for function.

Nobody speaks about how the widgets should feel and interact, but that's exactly what feels off about "GTK" on windows or macos. QML, Electron and partly GTK3 brings that feeling to all platforms. My biggest letdown is QML, as many QT developers see it as the future so it has a larger adoption than it should have.

It breaks just about any rule in the book: poor behavior on any platform, noticeably slower, style not consistent with the platform, broken scrolling, broken text editing, broken text rendering...