If you don't take advantage of the Github social features, which is essentially what Github is all about, I don't think your opinion on the matter is worth sharing with everybody, no offense intended.

One major thing that bitbucket does better: giving you information about a commit. It has side-by-side diffs, and while you're looking at a diff, you can expand the context easier. See a few lines have been modified but can't tell what method was modified? Click the ellipses and bitbucket will ajax in more context. In github, your only option is to go to the file itself and match up the line numbers from the diff (even worse, there are ellipses to click on, but it just jumps you to some random point in the page).

The only thing I miss in bitbucket from the github world are gists.