I'm not really a programmer (I only know a bit of java and c++ atm), but I have followed the development of unity and gnome-shell since they first appeared.



Early on mutter had serious performance issues, and afiak thats why they decided to switch to compiz (compiz was also a more mature project at the time). B



ut now it seems like its the other way around, mutter/gnome-shell runs smooth as hell for me and compiz is quite noticeably slower (and less stable, I've never had mutter crash on me, but I've had quite a few stability issues with compiz since the 0.9.x series. 0.8.x was pretty stable for me)