Don't know if people are dual booting.
Try it out on USB. It will be almost as fast as it is on your HD. This
way you can also see if everything is the way you want it.
You could also get one of those vmWare builds and run it in qemu or
the like but beware!
It would be better to build your own image.
In the last part of the build instructions:
Copy the image to a USB key
Use image_to_usb.sh to copy the image to a USB key. Do this outside
the chroot environment. (If your USB key seems blank, you're probably
inside the chroot environment.) Make sure you have a 4GB USB key.
./image_to_usb.sh --from=~/chromiumos/src/build/images/SUBDIR --to=/
SUBDIR is the subdirectory created by build_image.sh, and USBKEYDEV is
the device for the USB key.