Beginner users (and non-Macheads) hate it, but I've yet to meet a switcher than didn't like it in the end.
It's a matter of paradigms - Windows doesn't really have a lot of inter-app interactions via the default UI, so there's no real need for multiple apps to be visit at once.
I think you're on to something there. Good point.
Taking two windows, tiling them side-by-side and maximizing them should be effortless. It shouldn't take a fancy hardware set up nor an expensive investment, and it shouldn't be hassle to install. There's no reason UI widgets I don't need should consume precious real estate when I don't need them.
I develop on a 13" MacBook, btw.
It is amazing, well not really when you think about it, how much faster you become when you dont have to keep moving your hand(s) off the keyboard.