Average pizza with not-so-good crust (sort of a blander Domino's) but great cheese and fresh toppings due to high turnover.
They deliver all day long every day starting early, including Sundays, and the pizzas arrive in under 45 minutes. They're the only company in town that seems to understand that fast and reliable delivery means return business.
Prices are 'fine', you're not going to be impressed but you also won't be annoyed after paying like with Roman Candle or Ian's.
If you're wiling to go out for pizza there are about a half dozen places that are much better, but for affordable pajama pizza delivery any time of day Glass Nickel has cornered the Madison market.