On my Acer Aspire One (1.6Ghz Atom, 1Gb ram) with a 2Mb/s USB stick I counted about 16 seconds to boot from selection, overall about 30 seconds with my BIOS boot.
Couldn't get Wifi to connect, and a lot of missing features.
Very interesting though, could be perfect for quick kisok-style applications as well as a quick boot loader - looks like the plan allowing other OS's to be booted into from it.