I started the long march which was like a trip on Mars. The new Ubuntu with
Unity has some beautiful things, others are just too hard for the average user.
I admit I did not have enough time for playing with it.
Up to now I have not managed to get Empathy, then Pidgin, then Kopete to work.
The UI is fine, but for me it is easier to launch the programs from Xterm. I
made a desktop launcher for Xterm because I could not find the Terminal
anywhere. The workspace switcher is OK.
Surprise ! It seems there is no aptitude. I installed it
sudo apt-get install aptitude

The saviours were the other DEs and WMs. I ran LXDE. No problem. PcManFM
crashed four times. No problem.

Now I am writing under Mint, in plain old Gnome with Compiz.