Quick rundown on my opinions on various UIs:
- Atari/Amiga: Straight, honest frontends with some fun and personal touches that made you smile even if something went bad (guru meditation, busybee, bombs etc.)
- NT4/Win2k: Industrial like interface, really efficient, has a few gaping issues such as lots of messy tabs and checkboxes.
- Win7: Ok to use but feels quite pale.
- OSX: Great looks, great apps but it somehow feels disconnected. Maybe I didn't have enough screentime but it always felt like somebody elses desktop to me.
- Gnome2: I used and liked this one. Nautlius was a work in progress and was never quite there but it was a sane approach on flexibility, HIG and nice looks. I think that's why the initial Ubuntu was successful.
- KDE3: I never really liked it, it felt like windows with strings attached.
- KDE4: Never used it. The reviews turned me off and I was solid in the GTK app camp.
- Gnome Shell: Unusable mess. Insanity. No shutdown button? Seriously? Broken taskswitching? Ugly spacing and default colors without an obvious way to change it? I'm outta here.
- Unity: Same as Gnomeshell except that the colorscheme is even worse and I can't even turn of or move the dock. It's supposed to be docky code but no effects and options. Great! A combined menubar? On Linux? That doesn't even work? File searching with strange suggestions? I could go on. No, sorry Mark, I'll try something different.
Right now I am running the PPA from the elementary OS guys and I must say I like what I see so far. A plain working toppanel, a neat dock and of course modularity as a integral part of the development. Something I appreciate a lot on a Linux system. (Don't like plesk? Use docky. Don't like the WM? Change it. Don't like the filemanager? Use something else. Want a systemwide searchengine? Install Synapse. etc.) Slingshot is a fashionable Applauncher but also gets the job done. Most decisions seem solid and reasonable to me. I am really hoping this project gets traction and continues. Otherwise I don't really know where to go. XFCE actually works, but it's 2011 and I want a working and a pretty desktop. I am staring at it all day!