This is the part I'm worry about Apple releasing Yosemite as public beta when so many people will jump on it... Wonder how many people will read this before flipping the switch
Enabling iCloud Drive
After you install the OS X Yosemite Beta, you will be asked whether you wish to upgrade your account to iCloud Drive. If you choose to upgrade your account, iCloud Documents and Data will be disabled on devices that are not running OS X Yosemite or iOS 8. iCloud Drive will be available only on other Macs using the OS X Yosemite Beta and iOS devices running iOS 8. If you want to continue using iCloud Documents and Data on devices with earlier versions of OS X and iOS, you should not upgrade your account to iCloud Drive.
Next complaint is... Yosemite sucks, I can't get to my iCloud documents from iOS7 / OS X 10.9