Metallica and Guns N' Roses (as much as I like Gun N' Roses) shouldn't be mentioned in the same breath as those English bands.
I think an argument could be made for Metallica. They have been influential on many bands. They have a TON of great songs. They are a pretty good live band (well, I've only seen them once but they were great then). They have stayed fairly relevant for the past 25 years.
Guns N' Roses may not be on the same level though. The reason is that their music catalog isn't that deep and they didn't stay together all that long. However, I'd put Appetite for Destruction up against any single album that Led Zepplin, The Beatles, Queen, or any other band and I think it would be on even footing as far as musical and lyrical quality go.