I've used Linux for my home computer for quite some time. Have another at work and support Windows 2000, XP, Vista and 7 at work (a small but very busy retailer). I inevitably get a few questions from some of my non-computer-literate friends who own Macs (on my recommendation). I don't hear from them too often, though.
This means that I have experience using all major desktops. Overall, I find Windows of any kind to be the most irritating to use. Mac has me irritated far less. The concepts used in the Mac UI, although uniform and usually simple and usable, feel very limiting to me. Yeah, I hear ya on the window resizing thing.
Recently, I changed from Slackware/Fluxbox (after using others for quite a while) to Ubuntu 10.04 (LTS). Added the Mac theme for fun, and it does have an intermittently appearing global menu bar (not all applications support it) - that takes some getting used to. I like the Cairo dock, and have used some form of dock for quite a while now. Kinda like the theme, in spite of the Apple logo that appears in the top panel. After a mostly painless install, this is my preferred desktop. It combines some of the polish and usability that Apple is known for, while still retaining some of the Linux flexibility.
I do like the idea of Wayland, even if it doesn't pan out. A reworking of X sounds good, too. Not so sure about the one-size-fits-all nature of Unity. But not trying something new means never knowing what works - or doesn't. Or how to change that something to make it work. This is how progress is made.
I prefer the various options available to me when it comes to UI. The choice available is one of the best things about FOSS. I like the choice of trying something new, as well as the choice of reverting back to the old if the new is not my cup of tea.