I don't have a great deal of their catalog, but their first album was a great debut. I didn't think I'd like them at first, but I likened them to a rougher version of Foghat. I saw them on what I think was their first Chicago appearance - at Fremd High School in Palatine. Rush, who were awful, opened. KISS put on one of the most intense and entertaining rock shows I had seen. These weren't stoned hippies, meandering about the stage. They were a military precision team in action - guitar necks all at the same angle, movement choreographed. If you ever wondered where Motown fit into KISS, look at the care they put into staging an event. Much the way that Motown learned to entertain, KISS took that lesson into the rock world. I think only Alice Cooper has a better rehearsed show.
I saw KISS again about 8 years ago, and they were just as good. They are well worth the price of admission, without having to care about their records.