Got my first one with an iMac back last month and just received a new on for the MBP the other day. First place, I really like the low profile. Other mice (including the Mighty Mouse ) raised my wrist too high, and cut off my circulation. Result: cold right hand all the time. Now that's no longer an issue. Secondly, getting rid of the scrollball is a major plus for me. I hated to lose the side buttons, but hot corners takes care of those features nicely. Ditching the scrollball was more than worth it. I also like the two fingered swipe for surfing the web. Overall, hands-down the best mouse ever for me. As far as customization, the one option I know of it BetterTouchTool. I believe there's another app, but can't remember it's name. Any suggestions?