I admire both Canonical and the Gnome team because they made bold decisions and innovated the desktop. Unfortunately they moved into directions far away from how I like to use my desktop. At least I hope Canonical succeeds in giving us a device that can be both a phone and a computer. My dream is a 100 g (3.5 oz) device with the same computing power of a quad core i7. Many years to go.
Disclaimer: I'm using better and worse in a subjective way in this post. I'm not deluding myself by thinking that everybody must agree with me.
I started using Gnome as my primary DE in 2009 coming from XP (Vista being the alternative, ugh). Gnome 2 was vastly superior to XP. More beautiful and less clicks to perform any given task. So we might argue about what's better, Gnome or OSX, but in my experience both of them are better that XP and 7 (*). I won't even start talking about Windows 8. All my friends hate it but they decided they won't downgrade to Windows 7 (too complex to do) or switch to Linux, which is a know unknown to them even if most of them are using only Openoffice and Firefox/Chrome on Windows and very little else, no games.
(*) Actually I never liked Mac's top menu (since 1984) and the dock (it's distracting). I'd say that parts of Windows GUI are better than OSX (the windows and start menus) and parts are worse (pretty much everything else).
Given a choice I'd take a configurable OSX, to get rid of everything I don't like so you won't be surprised if I liked Gnome 2. I configured it with only a bottom panel and I added the Compiz cube to manage virtual desktops. The visual 3D effect while switching helps me remember where I am in desktop-land. I've been happy with that arrangement since then.
I occasionally had to use a Mac and I kept disliking the main ideas behind its GUI. I also occasionally had to use Win 7 and I didn't find it any better than XP. It has the same odd dynamics of waiting until a pendrive registers in the system (how can Linux make it happen instantaneously?), having to negotiate that maze the control panel became along the years, or having to install drivers to make hardware work (**)
(**) If the hardware is very new maybe there is no Linux driver, game over. But otherwise it's plug and play. My webcam, scanner, network printer, camera and smarphone (as USB drives) worked without me having to do anything. Why not on Windows?
I used Gnome 3 and KDE recently on a new PC because I run into some bugs with my Gnome Classic desktop (which - btw - is GTK3, not 2). I ruled out Unity because of the top panel and the launcher. Too bad because the HUD and lenses are useful but it's all or nothing. I tweaked the Gnome shell with extensions until it looked almost like my old desktop. It was not as good as that and before I even started to tweak the theme (the default is ugly black) it started freezing from time to time. So I gave a chance to KDE.
KDE was a good surprise at the beginning. It's very easy to make it behave like my old desktop, however it lacks polish and usability. All the DE have a Redmondian sense of aesthetics and interactions that makes me feel odd at using it. At least it seems that they tried to clone and perfect Windows 7, not 8, and they succeeded. However they perpetrated those same Windows's original sins of hiding external drives in the tray icon bars, too many clicks to do anything, etc. It's a good DE if you come from Windows but it tastes bad if you come from Gnome or (I think) OSX.
I eventually found fixes and workarounds for the bugs I was experiencing with Gnome Classic so I'm back to it. That's a clean and simple desktop and it suits my needs.
To recap, my hierarchy is Gnome 2 > Gnome 3 > OSX/Unity > KDE > Windows 7/XP > Windows 8 with the OSX/Unity not being usable by me because of insisting on the top menu and dock/launcher.