I backed up my iPhone that was running beta 1 to iCloud, then reset my iPhone to the beta 2 build, and chose to restore from iCloud backup. Data transferred and apps downloaded but app data did not apparently, as I have had to sign into all my apps again that have never made me sign in again after restoring from backup. I'm wondering what other info was lost besides credentials. Did you encounter the same problem, think if I tried it again it would transfer that data?
App data not transferred with iCloud backup
Resetting my device and restoring from an iOS 8 iCloud backup worked as expected.