Yup. On 10.10.4, I'm getting spinning beach balls even just configuring the settings, having installed a brand new BootCamp VM, before even loading the machine. It seems to be causing problems in Yosemite itself as well; other apps are stalling and stuttering (albeit nothing's crashed).
I run BootCamp directly from the partition. In the past (even pre-Yosemite itself) I've had the issue where the VM just grinds to a snail's pace (takes 20 minutes just to log out with no apps running); I've found that deleting the bootcamp VM from the machine library and recreating it solves that issue. This time it re-occurs much sooner; seems to happen if I let the Mac sleep for a long period with the VM running.
I know it's beta so caveat emptor but it's public beta so VMWare should be all over it.
I should add - I'm running on a mid-2011 iMac and using a second iMac (2009) as a second display via mini-displayport.