Actually, I said it earlier, there is a huge difference. BG are MUCH more progressive than any of those other bands. Just listen to their song structures - that is fucking complex. I don't even know how they rehearsed the songs for A Night at the Opera.
I'm not sure what metal isn't cheesy by the way. I guess 'cheese' needs to be defined because I'd love to know how songs about Satan, Egypt, mass depression, politics, nuclear war, space, forests, etc isn't cheesy.
I just figured everyone accepted that, you know, just because they listen to metal.