Cool, looks good. Minor stuff:

• Loss of headers in description blocks is a little confusing if remarkup fields are present, compare "Description + Personnel" to no headers:

• I think this is from earlier, but if you make the page short (or add lots of items) they become visible underneath "collapse". Without the spacer that this change removes, it is probably impossible to click the last item if the menu content is longer than the page content and window, because I expect it will be completely hidden by "Collapse". Here's a screenshot:

• Background grey on members/watchers feels maybe a touch dark? Not sure. Buttons look a bit weird at first glance.
• "Watch Project" feels kind of floaty/random? Not necessarily bad, but I did sort of like it right next to feed since it helped imply what watching does. Watching may be more obvious now that there's no subscribe, though.
• It is now impossible to flag projects from the UI. I'm fine with dropping that, but we should probably un-implement FlaggableInterface if we do.

This is all fluff, only actual issue is the bad merge (I think?) on the "adjust defaults" code in PhabricatorProfilePanelEngine.php.