I was about to make an 'erase and reinstall' with OS X Yosemite PB3, but luckily I saw the missing Yosemite PB3 in my purchases in App Store... Think I'll have to wait then. Maybe PB4 or something else coming soon, as some of you have mentioned!
Edit: Anyway - so I did the erase and reinstall, but when I got to the part of reinstalling Yosemite on the OS X Utilities-screen, the following message showed up: 'Reinstall OS X Yosemite failed to open, try again later' - or something like that. Tried a couple of times but it didn't work out, so I went on and reinstalled Mavericks from the Internet Recovery... feels almost as being pulled back to the 'stone age' after getting used to Yosemite - can't wait to install it again.