About Mastodon, yeah they are incredibly overrated. Okay band, but nothing out of the ordinary.
I don´t know if they have fans here, but i think QOTSA's last album, like Clockwork, was mediocre. Everybody seems to think it's amazing, but i don't see it. boring piano ballads, no good riffs...meh.
In fact, their last good record was Lullabies to Paralize (and it has it's bad moments). I think Nick Oliveri's influence and attitude is sorely missed.
And for the record: Kyuss >>>>>>>>>>>>>>>>>>> QOTSA.