I have been using Ubuntu for 3-4 years now and have been using it for everything from day-to-day stuffs to development. I am quite happy to see how Ubuntu has matured during this time frame.

But, I wish some improvement is done on improving hibernate. It takes ages to hibernate and system sometimes freezes. Moreover, my experience with battery life on Ubuntu vs Windows suggests Ubuntu manages power poorly.

I haven't used Unity yet but look forward to trying soon.