In case you haven't caught this bit on gaming news sites around, Insomniac is currently down to a staff of about 6 people and only one of them has experience in dealing with server issues. They've had a lot of jumping ship to other studios such as David Jaffe's Eat, Sleep, Play.
The ranked servers should be marked as such in the list. Most of them are run by Sony and Insomniac themselves and should have a green dot beside them.