There will be more offline capability with the new chromebook, and the updates to the old versions. http://news.cnet.com/8301-17938_105-57467667-1/hands-on-offl...
That's a bit of an unfair comparison. The surface works entirely offline, if you're using it for offline tasks. The Chromebook also works offline if you're using it for offline tasks.
The number of offline apps available for chrome is pretty limited, but so is the total number of apps available for winRT. as far as i can tell, both of these devices are basically just a web browser plus potential.
I've got a chromebook in the office as a test machine and its a fancy brick without a network connection.