I was testing this last night. It reduced the time for the emulator to cold boot from 120-130 seconds down to 45-55 seconds. Not as snappy as the iPhone simulator, but over cutting the time by over half is really substantial. Props to them.
Literally 6 seconds after typing "emulator-x86 -avd TestImage -qemu -m 512 -enable-kvm" and hitting return, until I'm at the Android login screen.
This laptop has an i5-2520M CPU @ 2.50GHz, 8GB of RAM and an SSD.