Really nice thing. First of all, new workspace can be added when needed and removed when no longer useful. Application can be started in any workspace using drag&drop, windows can be very intuitively moved between workspaces as well.
Finally Alt+Tab done right. It's amazing, how little was needed: support for arrow keys and mouse. Grouping by application first seemed unusual, but became loved feature after discovering Alt+` hot-key (switch between same application windows).
- Overview mode
Generally nice idea. All applications, recent documents and places in one place. The only disadvantage I see is windows in workspaces, which are a little to small to identify on my screen. You have to get used to look at applications list for running applications, rather then looking at workspaces. Unfortunately, I was somehow intuitively looking at workspaces and trying to identify things there.
It's always nice to have search feature. Looks very promising, if it will be well integrated into entire desktop.
New notification system is really great. Not everything worked well on my system, but it all looks really great. I wait for the stable release.
- Launching applications
Launchers in Gnome-panel are very useful. I miss something like that in Gnome-shell. What about hot bottom left corner, something like notifications?
- Application menu
Favourites are great, but the list of all applications not very. Categorised view is better for my taste and I hope to see it, when final version ships.