I'd say that a well-configured Linux desktop, which is not that difficult to do, is pretty close behind OS X for visual aesthetics and comfortably ahead of Microsoft. That's pretty damn impressive for free software versus two multi-billion dollar companies with thousands of paid developers and designers.
I only have 1920x1200 displays, but it's a cinch to make KDE, GNOME, and Cinnamon look beautiful on them and I switch between them periodically just for the fun of it. I haven't toyed with Enlightenment, Ubuntu's Unity, or Xfce in a while, I'll give them another go sooner or later.
The only "usability" issues I encounter is with applications that just aren't Linux compatible. Citrix claims that their "Gotomeeting" client can work on Linux but is unsupported, but when I try to join a meeting from Linux the Citrix website gives an error and won't even let me download the client software. I recently had a colossal .xlsx file I had to modify for work. Google Sheets couldn't open it due to the size. LibreOffice, Calligra Sheets, and Gnumeric could open the file but each would lose some of the contents when I tried to save it. So I'm stuck booting into Windows to work on that file too.
But 98% of my work and 100% of my personal computing is just fine from Linux. Much Ado About Nothing.