Been running it on my own machine for a few weeks now. Some things that I really like:
- Higlighting with Cmd-F search. I can finally see the search result instantly within any app!!
- New Tarminal and Console.app
- The “modal” Software Update ie shutting down all open apps before installing updates. The lack of this is the biggest reason why so many OS X users had system trouble after a SU. Finally!! I've been waiting a long time for this - this is actually how SU worked before in OS 9. :)
- Mail Notes. With .Mac, you just write a note on one machine and it shows up in your inbox on other machines. Pretty useful for todos and reminders.
- iCal icon :D
- Cmd-Option-B focuses on the search field in the history page in Safari now!!
… and a ton of other details I've forgotten to mention (I've always believed the true reason to upgrade Mac OS is in the countless details and not so much in the few big name features).
After using, the “3D” dock actually makes more sense to me, the only downside of it is that windows still snap to the edge of it when resized. Speaking of the Dock, the indicator bubbles look kinda silly but there's a way to replace them. I also wrapped those instructions into an easy-to-use script.