I've been running the Beta since PB4, and had the same issue's as others, i.e. no upgrade offered to people running PB6.
In the end I just downloaded the whole thing again from the app store. Took 45mins start to finish, went without a hitch, at least for me
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Did you lose any of your data etc? I don't want to have to reinstall everything etc.
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Currently running OS X 10.10 (14A388b) which is PB6, downloaded all the Pages/iPhoto/iTunes updates though.