So Apple has released Mountain Lion OS X 10.8 via the Mac App store for $19.99! Sure are undercutting Microsoft there, and with a year between released they can really add in the near and the short term.
So far my favorite part if that Contacts has returned to a 3 pain view so you can see the groups and contacts at the same time as you could before lion. Still hate the B&W icons in the Finder Sidebar, and the stupidification of the OS (such as hiding the User/Library folder).
Also had some issues, lost the icons in the sidebar and had to dump the sidebar preferences to fix them. The finder also ground to a halt after the upgrade, but I fixed it with Diskwarrior. And I have had some scrolling issues where I would scroll and it would instantly jump back to the top. And Launchbar had to wait for the OS to re-index with Spotlight before it worked (wow, I can barely function without Launchbar at this point). Had to change the settings to allow all apps to launch, so I could install apps from anywhere to get everything working though.