I have just updated my Ubuntu 10.10 installation to 11.04. To be honest, I do not like the new Unity interface. I would say the old Gnome interface is much easier to use. Windows 7 is also way better. I might be able to get used to it in the future, but for now I will go back to the classic desktop and wait for Ubuntu to fix the Unity interface.
1) The launcher is basically useless, the autohide works too well so that it does not come out when I need it from time to time.
2) Software center is getting better but I still prefer Synaptic. Anyway, Synaptic is still there.
3) There is no "Show Desktop" icon. This is not that bad but still I prefer to have it.
4) I miss the gnome-panel applets.
5) I do not like the global menu. This is the most annoying feature. I do not have a Mac and I am not used to this "feature".
6) I do not quite like Dash, I prefer the old Gnome menu system where I can access the applications with less mouse clicks.
Anything I like about Unity? Nothing!
I think Unity will be like KDE 4 when it was first launched (I still do not install KDE now) and it will take some time for Ubuntu to fix it. Maybe Ubuntu Unity can get usable next year, say 12.04.
Anyway, there seems to be a good guide for those who want to use Unity.
Edits on 1 May 2011:
After disable the global menu and fix the launcher to never hide and add some common application to the Launcher, the Unity Interface is at least tolerable again.
Still need to find a way to move the maximize/minize/close buttons to the right when application is maximized. When it is not maximized, the buttons are on the right which is fine, but they move to the left when the application is maximized. This is quite annoying.
Notes on 17 July 2011:
Enabled the global menu for a while and still does not like it very much, but it can be tolerable now. And I keep the maximize/minimize/close button to the default left side now.
So Unity interface is usable now, but still not that good.