I saw Bon Jovi open for Judas Priest in Vancouver during Priest's "Turbo" tour. I remember being TOTALLY blown away at how bad he sounded. His voice was thin, weak, waaaaaaaay too quiet, and he had no range. The backing vocals, on the other hand, were HUGE. I remember thinking that they should just let any other member of the band take over the lead vocals that night so that some justice could be done to the songs. I liked Bon Jovi a lot at that time, and I was extremely disappointed. A couple years later I saw Tesla and Def Leppard in Vancouver, and Jon Bon Jovi was in town. He got up and sang a song or two with Def Leppard. Same result: he was pathetic. I remember thinking, "Geez, Jon, get off the stage and let Joe Elliot do his thing!!" Joe was brilliant that night.

I don't think Jon was ever that good a vocalist. That doesn't mean that I don't enjoy his music. I enjoy a few bands with mediocre vocalists: Poison, Motley Crue, Ratt, etc. (ironically, many of the vocalists whose names have come up in this thread).