While I'm usually a fan of dive bars this one is not really my style. If you went to Miami or OU you might feel at home amongst the overwhelmingly fratty clientele, and you'll probably see some people you know there if you graduated in the last 3 years.
As far as ambiance think recent college grads going into corporate jobs still desperately holding onto college.
On the upside if there is a game it'll be on there and there's always cheap booze and skee ball. Plus, you will likely get to indulge your late 90s/early 2000s nostalgia when they inevitably play backstreet boys and/or blink 182.
Wound up there last night, things were kind of slow on W. 6th until relatively late. The Stanley Cup game was on and we wanted somewhere cheap to drink and watch the end. It was empty when we got there and didn't really fill up for 20-30 min., it's definitely a later night spot. Got a g&t and a shot for 8 bucks so you can get quite a bit for your buck if you are a beer/shot person ($3 beers/shot specials every weekend).
So, if you are in the mood for reliving college and hanging out with 20-somethings in a mildly damp underground bar that smells like an old leaky basement, or you just want some cheap booze and a place to drink it, Dive Bar is the way to go. If you are looking for a sophisticated evening... well you should probably go somewhere that isn't called Dive Bar.