I have never experienced this in 2.0b1 but with 2.0b2 i have the following symptoms.
When i put my Mac to sleep with a running VM the System reboots after hitting the keyboard to wake it up.
In 2 Cases my mac reboots when i restarted the vm after the above mentioned hibernate-reboot.
For the record:
I have a 1GB VM with 32 Bit Debian (Lenny) on 8-Core MacPro with 12GB , no other VMs running currently.
Greetings DaKoba