Since Chrome quietly updates, how do you think they'll handle updates that have significant UI changes? I guess you can have new versions have some features opt-in? That's what they've done with the GMail transition.
The main idea around Chrome is no significant changes from version to version. If you look at Chrome 9 and Chrome 15 you'll see there are significant changes but they were made in small iterations with each release.
The benefit of this is if they make a small change that causes a large pushback, they can easily stop that path of development and try another.
