There are no timelines that I've seen for Chromium/Chrome on the Mac, beyond "we're working on it." Chromium builds will continue to evolve, apparently at a rapid pace, adding features as time passes. At some point, Google will announce that Chrome for Mac is ready for use (probably as a beta), and we'll be able to take an in-depth look at it.

For now, though, Chromium is out there. It's usable though far from feature-complete, and it looks to bring some interesting new features to the browser wars. As a browser enthusiast, that's nothing but good news in my book.