Just a quick update as I received a message on Yelp from one of the owners - I'm told they are now accepting phone orders, and will soon start accepting online orders; they didn't initially do so in order to make sure everything was running smoothly first, and I completely accept that explanation. As the lack of phone/online ordering was the only reason I deducted 1*, it's only fair to bump them up to 5*. I also appreciate that they reached out to me, which shows they care about the customers.
To recap my prior review - Vegas is super lucky to get what is my favorite all-around Chicago deep dish spot; this Giordano's is the real deal, existing fans shouldn't hesitate to eat here, and those who have never tried it should definitely stop by.