There site is..the actually OS is based on Ubuntu with a custom HTML5 skin on Gnome 2.29. This allows them to do anything GTK programming wise. This is why there is Libre office, Skype and other fully native apps.
Even on a high end SSD it still can get under 10 sec boot. Plus you still have at the issues you get with a full desktop experience...even if it is more walled off. xorg will still have the same issues. Plus all the wasted drivers kmods and code that slows the machine down. Chrome OS has the benefit of only running on a handful of machines and run fast...that is the point...and I know I bring this up a ton..but Verified Boot process is the most important part of Chrome..You can NEVER get a virus..any bad code will be removed at boot because it won't pass the Key check..and since it is all in the cloud...when you log back in you get everything back...
Amazing how good Chrome is.....