The experience got terrible reviews in Phoenix. It was retooled for San Diego and Dallas and seemed be reasonably well received. The summer tour started off in Philadelphia and just ended and the rest of the tour was cancelled.
I actually went over the weekend in Philly. I thought it was fun, but overpriced for face value tickets (we used Groupon to go which put the price in a tolerable range that I thought was acceptable). It seemed pretty empty when we went (afternoon on July 4 so it might have been the holiday playing a role) but that allowed us to linger and spend as much time on stuff as possible. The two main shows -- the projection dome and the ride were decent but no where near as good as theme park stuff; understandable given the temporary nature. Still not all that impression once someone has been on Spider-Man at IOA.
I think the concept was quite good and many of the components were enjoyable enough, especially for children. There probably needed to be one more larger scale experience to make it more fulfilling. Also, the price point needed to be fixed -- tickets were in the $40-60 range for Philly which is pretty costly for a whole family for a 2-2.5 hour experience. I think they need to be more like $20-30 for children and $30-40 for adults to be satisfying for what was offered (we ended up paying $30 for child and $45 for adults with the Groupon).
I suspect it was cancelled due to poor sales and losing money. Like I said, it didn't seem very busy and having a Groupon available (for most if not all of the show dates) seems to indicate lackluster sales.