I think Cobain is a ge-- was a genius. Nirvana and a few other seattle bands revived hard rock, and held off rap for another 5 years or more. The most energy and innovation comes from unstable people who burn themsleves up - James Dean, Monroe, Hendrix, Morrison, Bonham, Belushi, Cobain.
Check out Bleach, Nervana's first album. My favorite is In Utero. They are saying "F*** our success, we dare you to play this on the air".
But when it comes to grunge (I hate that word) bands, I prefer STP, Screaming Trees, and Alice in chains over pearljam and soundgarden. When I am in the mood for Alice, I will listen to Grind and Again 5 times in a row. I love that self-titled AIC album.