Trying to find Secret Pizza my first time was hard. I was about 3 pm and we were just wondering around the third floor of the Cosmo and had to keep asking around where it was. We had passed by this obscure corridor a few times and had no idea that was the entrance to Secret Pizza. Well I guess that's the secret. Try finding this place at about 2 am is a lot easier, there are tons of post night clubbers, or other late night eaters trying to get their grub on. You'll most likely see a line into the hall or at least bunches of people scarfing down pizza near the entrance.
As for the the pizza, it's not like there are crazy weird toppings or anything. It's just a plain and simple good pizza. They are constantly baking them so they are coming out hot a fresh. They are just under $5 a slice, which may seem like a lot, but they are large like Sbarro, but wayyyy better. Keep in mind you are on the strip trying to get food. They also sell beer on tap and soda too! I love the white pizza, but I usually select whatever just came out of the oven, and haven't been disappointed yet.
Overall, it is something to experience once. You feel like you a part of a secret club, secret pizza club that is. I can almost guarantee that after trying it once you'll be back again.