Been there a couple times just to experience the venue. Last time was last fall with a buddy from New York. It was almost a religious experience. They've really dialed up their game since I saw it before, maybe late 1980's where there was almost nothing noting the Holly/Bopper/Valens show. My buddy was so moved he bought a book about that last tour.
Only actual show I saw there was the 50th reunion in 2009. Rumors of a McCartney appearance were circulating. He did not come but saw Peter and Gordon, Graham Nash, Chris Montez, Wanda Jackson, Los Lobos, J.P. Richardson Jr, Dave Mason. And my personal favorite at the show, Sonny Curtis.
My buddy works for KCCI and got to cover it for the station. He got me in as his assistant. So I worked 1/2 a day in Rock Island, drove up and saw the show, then drove back, getting to bed about 4:30 then up for work at 6:15. Plus, like the original show in 59, it was cold as ****! I was not on top of my game.