Installed on a 2012 Mac Mini, no problem so far, but then I rebooted and it got stuck.
Tried safe boot, no luck, started up in verbose mode, it hangs at : pci, waiting for SDXC, I removed that extension, still no luck.
Removed all logs from all Log Folders, I thought I could see the cause in the logs after trying again, there where no logs after a resart, I also removed all caches, after a restart all Cache folders were empty.
This tells me that it got stuck early in the boot process or the permissions where messed up, if that is the case then even the System can't write to the disk.
Sadly I can't repair permissions from Mavericks, the permission repair is greyed out.
I will try to start up the install again and see if I can repair it with disk utilities from within the installer.
Some nice features inside Yosemity, but, I don't really like the way they go with colours, like those odd coloured folders in the Finder, looks like cough cough...Windows.
Edit: Reinstalled, works, then restarted, same problem-hangs on boot screen.
Guess I wait for the next DP.