Particularly I don't like that the activity is now hidden on profile pages. I often like to look at people's activity, and it bothers me that it is an extra click away every time now.
I miss the blue to distinguish your own commits from commits by other users.
Information that used to be available right on top such as organizations, and people the user is following are now harder to find or below the fold (on my macbook air 11").
Also now that the filters on top have more emphasis (All, Public, Private, etc) I think they should remove ones that are not useful. For example I don't have any private repos or mirrors so I feel like there shouldn't be links to empty pages, but this is a minor detail.
On top of that I think the page itself has a bit too much white space. It feels a bit plain to me.