The Madison is a giant pub/bar, spanning 3 floors and multiple buildings. It's often packed on popular college drinking nights (Wed-Sat) but as far as college bars go, it's a better atmosphere than some similar options in the neighbourhood.
Drinks here are expensive. They don't sell pitchers, and you can expect to pay $6-$8 for a pint of beer, depending on what you decide to get.
Also, on the busier nights, there's a good chance you'll run into a line up. Lines move at a slow, but fairly even pace, so you can be happy in the knowledge that if you decide to line up, your slow progress is actually progress.