Secret Pizza is the worst kept secret in Vegas.
Yes, it's a secret in that there are no signs anywhere pointing to its location and you have to kind of figure it out on your own. But it's existence is no secret. (but you guessed that with the 3K something reviews, right?)
Anyway, we went here for late night and waited maybe 30 minutes in line. The reason it took so long was that folks were ordering whole pies and clogging up the pizza oven for those of us that just wanted a slice. WHAT GIVES! (jkjk)
I ordered the white pizza and at first didn't think it was much to write home about, but now look at me, days after my trip, still pining over it.
So yeah. You should go. Wait in the line. It's worth it.