I get a feed back request from Gmail, asking me why I am still using the old gmail. My main reason is, for the Gmail Contact only.
I don't like the previous "new" contact. It has 3 columns, looks like the Windows application or Outlook style. It leave me limited space for content editing. This type of design only suitable if you have a large display with high resolution.
The previous Gmail contact manager.
The new contact manager is more "Gmail-like".
Finally I don't have to go back the old gmail anymore.