the os is good but the UI sucks.
The unity crap bar makes it hard to launch multiple windows of a program, requiring you to basically use options built into the program to open another window
the side bar is annoying, when ever you go to click on something on the left side of the window, you can easily accidentally bring out that annoying menu
the search bar is annoying and will at most drive new users away from ubuntu. Since it requires you to search for things, for a novice user if you don't know what specific option you are looking for but want to discover the options, this makes it hard to do.
while hardware support has been getting better, the Os has also been getting slower overall. They need to shift their focus from bloat to speed.
they need to take a lesson from professional software makers. Most new professional apps, eg check out the latest adobe audition or photoshop or maya 3d or the mental ray render engine
Performance is always improved on the same hardware
An upgrade is not really a upgrade if you are losing performance.
Would you "upgrade" from a GTX480 to a GTX460?