I was at the show. There were over thirty thousand people in attendance. All the bands played great. Joe Elliot's voice is pretty much hammered though.
I thought breaking down the demographics of the show would be kind of an interesting exercise. Last year Def Lep played the same venue with Journey to probably 7000-10,000 less people. If I were to guess I'd say that it was a combination of the bands that brought in the huge crowd. Def Lep on their own probably wouldn't draw more than 15k on their own and SLC has never been a big foreigner town. (I've seen several of their SLC shows dating back to '94 and they never drew more than a few thousand) SLC has always been a good place for Styx.
I know there are some on here who are critical of Styx embarking on tour as a warm up act. I have to disagree. During the Styx set almost all of the crowd was on their feet a rocking with abandon. I think it's cool that Styx can still get that kind of reception even with a mixed crowd. Hats off to my home towns fans for getting out and supporting three awesome bands. I hope we have more tours like this in the future.