i definitely like the lion functions and i most probably will upgrade to mountain lion but since i have it on my computer it gave me a hard time. obviously it doesn't do for anyone but for me some things still don't work - e.g. when i connect my macbook with the thunderbolt display the mouse stucks or my time capsule backup seems to never finish.
i talked to apple and i´m working with them on the problems. funny thing is that they don't have a solution so far ;-)