Summary: I was really looking forward to lion but my late 2010 macbook runs far slower on it. Also it now hangs on the login screen when resuming from sleep.
Pros: The fact that I can now do the most basic of function which is resize a window from any side
Cons: They did not change much. Saying applications like mail changed is nothing to do with the os, it was just released at the same time. It is like saying microsoft released a new outlook therefore its a new version of windows.