It's also funny, though, how selectively we remember things.

Only a few years ago Mac multi-monitor support was horrific. You couldn't straddle two screens with a window. And heaven help you if you were dealing with full screen, your second monitor was effectively disabled.

My experience is totally different. I use monitors of different densities every day, and move things between them, etc. Nothing bad happens, and maximising just works.

The only bad Windows density thing I run into is when I occasionally remote desktop into Windows Server 2012, which doesn't know about HiDPI or resolution changes, so if it starts on the wrong screen everything is hilariously tiny. That's fixed in more recent Windows Server versions.

I have a different experience. I connect to 3x HD monitors at work, one of which is portrait. At home I connect to a 3K monitor and a portrait 1980x1200 one. All works flawlessly for me.