I've had Glass Nickel for take out several times and just recently ate at the Atwood location. As mentioned in other posts, the feta pizza is the signature pie, but Glass Nickel puts together other good pizzas, both from their deluxe selections as well as made to order. Ingredients are fresh, and the pizza is tasty and well done overall. Check out their website for coupons.
I would rank Glass Nickel as occupying the space between your standard pizza place and gourmet-style pizza (do those exist in Madison?). So next time you feel like heading over to Little Caeser's for their $5 Hot n Ready, spend a few more bucks and pick up something you'll appreciate more.