I like a lot of their design decisions like the global menu, dechroming maximized windows, easy custom lenses etc. But the compiz/custom code base just isn't up to the task. Worse, unity is so tied to their non-mainline gui stack that it is a herculean effort to get it to run on anything besides ubuntu, preventing them from getting fixes from outside their ecosystem.
I know there is a lot of bad blood these days between gnome and canonical but they really need to bite the bullet and rebase on mutter, gtk3 & gnome shell. Canonical is great at a lot of things, but core performance oriented software just isn't one of them. Let somebody else do the heavy lifting.
I haven't gotten a chance to try the gnome shell spin that they're producing this cycle. Can anyone comment on how well its working? My experience trying to go vanilla gnome 3 on ubuntu in the past has been less than stellar, but I really appreciate the ubuntu community and things like launchpad ppas.
*250ms-2000ms lag