If you take it for face value, it looks like Google's intents are pretty benign. Although Rakowski's analogy comparing browsers to cars is a bit trite. It also appears that Mozilla was taken by surprise by this. It would be interesting to know if they were looped in on the project prior to announcement.
Also, I've had issues with PDF freezing the entire Chrome browser, so it appears they still have some work to do on the tab isolation concept.
Jake