I was a MacOS user from System 7 through to Yosemite. I now use Ubuntu 99% of the time (I still have a Mac that I casually use). IMO Ubuntu is now superior to OSX in almost every way. For me, Ubuntu really does "just work", and gives me a vastly better package manager, and the ability to use the i3 window manager, which has fundamentally changed how I use my computer.

I am specifically saying "Ubuntu" and not "Linux" because I don't care that it's a bloated distro, I don't care about tweaking things just right. I don't care about the freedom and flexibility that "hardcore" distros give you. I just want to turn on my computer and get to work, and Ubuntu gives me exactly that.