Fucking love them, although I think things peaked with Rated R. Not to say Songs For The Deaf or Lullabies To Paralyse are bad, I just think it's generally been going down hill since the second album. Also, the S/T album is one of the most criminally underated albums i've ever come across, especially given it's pedigree.
However, all that said, Kyuss have ruined QOTSA for me as they are simply so good, even the various products of the various members of Kyuss (QOTSA, Slo Burn and Unida in particular, as well as Fu Manchu [less dependant on Kyuss] and Hermano [just not quite as good]) are at the very least all worth a listen. Kyuss invented stoner rock in its modern form, and are one of those bands that sound like an intense drug trip, regardless of whether you're fucked up or stone cold sober.