We try and make sure that the Chromium blog (http://blog.chromium.org/) always covers new features as they make it into the new Beta. Imho you should be able to read the beta blog posts on that blog and not miss any new developer shiny things. Also fwiw we're going to try and do a better job of making the release notes link to the appropriate beta blog post on the Chromium blog, I agree we've done a poor job on that in the past.