First Google Chrome Metro beta just hit Dev Channel
Basically what the title says.
The two things I've noticed so far are that everything is separate between the desktop and Metro versions (signing into your Google account probably helps that with the syncing), and that while extensions are available, they can only be installed from the Chrome Web Store . Ones with binary components such as one variant of LastPass don't install; the non-binary version appears to work fine though.
So far though, it's basically just Chrome but with larger buttons.