Blurring the line between laptops and tablets while also holding that line. That's the tricky balancing act Apple is trying to pull off with OS X Mountain Lion. On the one hand, the new operating system for Macs is very iPad-like, from the iCloud-powered Notes and Reminders apps to Game Center and Notification Center. And yet it's clear that Apple very much wants to keep the desktop and mobile environments distinct. With more than 200 new features, Mountain Lion ($19.99) doesn't try to reimagine the PC as Microsoft's Windows 8 does. Instead, Apple cherry-picked some of iOS' most compelling features to make iPhone and iPad owners feel more at home. Does Mountain Lion succeed?