Jesus Christ. Okay, in short, ML fixed some but not all of Lion's issues, and Mavericks fixed a few more but introduced a lot of annoying "features" that still broke my workflow. Yosemite was another huge regression, almost as bad as Lion.

If you want more specific than that, you'll have to find someone who has spent more time than I have on those OS releases. I've tried each one and have yet to see anything better than Snow Leopard; if you don't like that answer, too bad. I'm done.