In the words of my own personal Vegas Wolfpack, Secret Pizza is.... "just pizza."
After hearing so much hype about this ultra secret pizza place on the 3rd floor of the Cosmopolitan... this place turned out to be regular pizza - gooey, cheesy, delicious. But not anything out of the ordinary. We came here for a quick lunch before starting the day (around 1pm - Good Morning, Las Vegas), so there wasn't too much of a line. Took 20 mins to get a mushroom pizza. It was a normal pizza - nothing to complain about. I think the appeal of the place is mostly its secrecy and the fact that it's conveniently located/open to service the drunchie-driven crowd pouring out of Marquee during the wee hours of the morning.
If you get a single slice at $3, it's a pretty expensive piece of pizza. However, the large pizza was split among 6 girls and came out to about about $2.50 each. They had told us the pizza was 12 slices so we expected 2/person, but there ended up being 9 huge slices. Maybe someone cut it wrong? In any case, we ended up with one and a half big slices per person.