The good: the large pink neon sign out front. Nothing says classic diner to me more than pink neon. Not as epic but in the same vein as the Save-On-Meat pig in Vancouver - pink neon will cure what ails you. Also, this place is apparently legitimately quite old as my girlfriend's parents used to come here when they were dating.
The 'ehh': Standard 'open late' chain diner fare serving a huge menu of stuff they can't possibly all do well. Seems like most of the positive reviews here are from post-bar/club patrons, so that'll give you an idea of the food. You don't 'go to Fran's' -- you 'end up in Fran's'.
The bad: Pretty expensive for the white bread diner food you're getting.