Here are some of my observations...
Background: Gnome 2.x diehard - it was the perfect setup for me but then Space Coke Mark and the GNOME Hippies had to go tablet on us.
KDE - Actually not bad, it's definitely been improving, but a bit bloated and just didn't feel right to me and had issues with some default applets. Don't wanna bash it, it's ok, just not my cup of tea.
Unity - ZOMG! THE BEST THING EVER!!! Just kiddin'
[a bit of vomit] Next...
GNOME Shell - Once I put in the MGSE, it was pretty usable, I liked the extra focus on the keyboard, needed to install Cairo and spend a lot of time setting it up to meet some additional functionality needs, but all in all it was resource-intensive, my fan was on at all times (got an old Lappy dual core 1.9GHz, limited to 4GB of RAM, shared with video), so I decided to see what XFCE was all about
Mate - Gave it a bit of a whirl in the early days but it was unpolished, didn't see much of a dev perspective in it and I liked GNOME Shell with Cairo better
XFCE - Tried it because I was annoyed by the resource hoggyness of GNOME Shell. Very nicely implemented on Mint. For some reason XUbuntu wasn't taking kindly to GTK themes. Works like a charm on Mint. Decked it out the way I had my Gnome 2.x with full functionality, even though you needed a rocket surgery degree to set up the panels, the Weather applet was moody as hell, Thunar's a bit buggy but they've made huge strides in useability and notifications weren't as nice as on any of the GNOME's. That's been my primary post-GNOME2.x DE as of now. Minor annoyance: Don't like the lack of preview in the icons once I got rid of Nautilus (as it was messing with my desktop icons, forget exactly how but it was annoying).
Cinnamon - Just installed it and set it up today, mostly as a result of Maya's coming. Might just be the one.. Haven't heard the fan come on even once, but it looks smooth and polished. Easily set it up to be pretty damn close to my GNOME2.x ideal. I also like the way the Menu works and cuts down on the use of the mouse. A few remarks:
-Configuration on the go!!!!!!
-Panels should be a bit more customizeable, like natively having 2 panels on the bottom. The 2 bottom panels extension is nice but what it really does is cover up the bottom of the application that I'm using. I'd also like to have more control over the sub-panels and icon placement in them.
-More theme integration - for example: If I like dark background with light text, I'd like for my applications like gEdit, XChat and Thunderbird to adopt it.
-Easier applet/extension/theme installing/upgrading. It was easy enough for me as I've been around the block, but a newb would need a bit of a crash course to get it figured out.
-Needs a bit of bug hunting.. Those baloons that come up with the application name when you hover over the quick launch icon sometimes won't go away and they cause a visual distraction. It displayed a bubble notification when I sent a message in Empathy but didn't display one (just a quick flash in the upper right corner but not enough for me to figure out what) when I closed the chat window and received a reply). Some of my packages have a blinking taskbar notification feature - Cinnamon should support it.
-Needs customizing the taskbar area - I like for the items to appear chronologically by default but still to be able to move them
-ALT+F2 was disabled by default for some reason?!
But all in all, it's going in the right direction and I'll probably stick with it when I dump Lisa for Maya.
Who I am: Seasoned Linux desktop user who dabbles a bit in administration. Been running Ubuntu since 2008 until Mark snorted up all that Space Coke and puked up Unity. Kept relying on Maverick as I wasn't buying into Mint until I realized that I needed to go with an actively developed DE and I read about Clem's team working on that on 2 fronts. That's when I gave Lisa a try. For work, I've mostly used Debian workstations, for embedded devices OpenWRT, for my personal server projects, CentOS, so I'm not buying Clem's toenail clippings on e-bay or anything like that
P.S. I didn't vote Cinnamon as I only installed it to give it a try after reading a couple of pages of this thread, voted GNOME Shell and XFCE as that's what I was using on this machine until today.
Certain "respected" members of our business community are unable to innovate so they like to patent the wheel and sue car manufacturers.