What this app really is is a mobile version of TKTS. Instead of waiting on a long TKTS line, you can just use the app for discounted (or full price) tickets. The other plus is that you do not need to wait in the Will Call line, they will have your ticket across the street from the theater -- you meet them there. Fast and easy. You do pay a $5 concierge fee, however. It's an app for those who want convienence (not to have to wait in lines).
I've used it a few times. The first experience was for THE GLASS MENAGERIE. I chose the Rear Mezz location and my seat was for the last row in the Mezz. Not a bad seat for that theater...but I felt that I could have gotten that seat a little cheaper elsewhere.
Second time was for ALL THE WAY. I chose the Rear Mezz location and my seat was towards the middle of the Rear Mezz, somewhat empty seats surrounded me.
I'm not sure if I will use them again. Probably only if I don't want to wait in line, or don't have time to print a BroadwayBox discount code and go to the box office my self.
"The Spectacle has, indeed, an emotional attraction of its own, but, of all the parts, it is the least artistic, and connected least with the art of poetry. For the power of Tragedy, we may be sure, is felt even apart from representation and actors. Besides, the production of spectacular effects depends more on the art of the stage machinist than on that of the poet."
--Aristotle