"100% native widgets" is the easy part and wxWidgets/wxPython is doing just that (and always have been). Providing higher-level API is harder and again, wx does

"100% native widgets" is the easy part and wxWidgets/wxPython is doing just that (and always have been). Providing higher-level API is harder and again, wx does that too. But the devil is in the detail. The reason why many wx apps don't look very well on OS X is because getting all the tiny details like spacing, behavior, layout etc. right for all supported platforms, with (mostly) same code base is hard - and it has nothing to do with the look of individual widgets. But well, you'll learn that during the journey ;)