I can't say that Foo Fighters is a favorite of mine, but I have to say that Dave Grohl has impressed me with his versatility and his commitment to the music. He's hard to put into a category.
As for the hype, the music media always picks out someone and plays it until the next big thing comes along. Whether it's Dave Grohl, Taylor Swift, Britney Spears, Ozzie, J Lo, Madonna, Harry Stiles, John Meyer.... it makes no difference who they are. Play that story until everyone is sick of it, the find a new target. I don't really follow the big media machines much at all. If I like the music, I listen.