Go and catch yourself a new kitty.
If you are looking for a good review/overview, Mr. Hackett at 512 Pixels has it dialed in.
If you are looking for a smart thought piece on Mountain Lion and the Simplification of OS X, Mr. Blanc has you covered.
If you are looking for me to say any more about it, well, you will have to wait. I personally like to wait a week or so before installing such new things. Not just to make sure everything works as expected but, also, to allow time for me to determine if I really need it or if what I have is enough for now. Heck, I might even wait until iOS 6 is ready because many of the features won’t work ideally without it.