I remember many years ago someone telling me how awesome Nazareth were. I finally heard them recently and concluded that... well, they aren't. They sound to me like a sort of proto Guns & Roses.
Nazareth is one of my favorite bands. They had some very commercial rock anthems (Hair of the Dog, Love Hurts, Dream On, etc) but they had some great out-there stuff, too. They were a big part of the early metal movement, touring with Deep Purple at one point. They fit in with some of my other favorite bands like Deep Purple, Black Sabbath, and Blue Oyster Cult. http://www.youtube.com/watch?v=z5SyetmQ6Xc, http://www.youtube.com/watch?v=WyorXkwfkLs, http://www.youtube.com/watch?v=PblMwPRjYms, http://www.youtube.com/watch?v=rb7VzULrwsc and http://www.youtube.com/watch?v=Wl_q9ZCoyOg are my favorites from Nazareth. I can easily see why someone wouldn't like them, but they are a very talented group of musicians. They sounded as good, or better, live as in the studio, which is something you just don't get today with all the auto-tuning, lip-synching, and whatnot. I think they are an awesome band.

Good catch on noticing that Dan McCafferty's vocals were a big influence on GnR, by the way. I've heard that Axl Rose wanted Nazareth to play at his wedding. Could be just one of those stories, though.