PROS: Cover Flow allows you to view bookmarks iTunes style, Looks elegant and loads pages very fast, Top Pages allows you to see your most popular pages at a glance, Reader allows you to view lots of content on one page, Private browsing mode
CONS: Not many plugins available, No way to change the font in Reader, Installs other components during setup
PROS: Plays WMV files in standalone Flip Player or QuickTime, Doesn't obscure playback with controls, Converts video and audio to other formats, Optimized for OS X 10.7+, Powerful tools for video editors working with WMV, Playback support in Office 2011 for Word and PowerPoint, Keynote can import Windows Media files through Flip4Mac , Supports video previews in Finder, Supports WMV in Safari, Firefox, Chrome and Mail, Official Windows Media Player
CONS: Does not support Snow Leopard, Does not support screencasting, Leaves a watermark in QuickTime, Advanced features only in Pro version
PROS: Closer integration with iOS for iPad and iPhone, Launchpad enables faster access of applications, New multitouch features, View apps in full screen mode, Autosaves and auto-resumes apps, Updates to Mail and Safari
CONS: Ideally requires a Trackpad or MacBook Pro for gestures, No more Front Row, No more Rosetta , No support for PPC anymore, Launchpad not much more useful than Dock, Replaced by OS X 10.8 Mountain Lion
PROS: Much closer integration with iOS, New improved Safari, More powerful Spotlight search, iPhoto replaced by Photo, Answer iOS calls on your Mac, iLife available for free for Yosemite users
CONS: Most new features iOS inspired, Flatter look won't appeal to everyone
