The good Interface enhancements make finding apps and files much easier A completely overhauled QuickTime X now sports a cleaner interface and recording tools Exchange support across Mail, the Address Book and iCal is huge for those who take their Macs to work The bad Snow Leopard works with Intel Macs only PowerPC users are out of luck Requires AU$39 upgrade fee Sneaking in a few days before its promised September release, the tune-up for Mac OS X Leopard costs AU$39 for current Leopard users, and packs just enough punch to be worth your money. Apple is careful to point out that Snow Leopard isn't a complete system overhaul, but rather a collection of hundreds of smaller refinements to make Leopard run more gracefully

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Snow Leopard (Mac OS X 10.6)