I just installed the public beta 1 of OS X Yosemite onto an older macbook, and apart from being a bit slow it seemed all ok. I decided to do the same on my 2010 Mac Pro which uses a RAID 0 of SSDs as the boot disk. After the initial install screens it rebooted and got stuck mid boot. I tired a couple of times with no luck.
Holding down option to choose a boot disk gave me 4 volumes (when I should have 1…?) I selected on manually and the system came back up into OS X 10.9 Mavericks. I can’t seem to find anything about it online, so to anyone else looking to try Yosemite public beta 1 on a raid setup, it may not go smoothly.
Back to 10.9 until the next beta release perhaps.