I am using ML for a week now and I am very much happy with it. It is a lot smooth.
I experienced considerable difference in boot up speed. I have a MBA 13' with 128 GB SSD. It boots up in 5 to 6 seconds. With Lion it used to take 15 to 16 seconds. A 10 seconds slash down is really appreciable. Great work by Apple as usual!
But I think that scrolling in launchpad is not so smooth. In lion, it was smoother. Give your thoughts on this.