I'll be honest and say for me, no one's come close to touching Kyuss at this sort of sound. I do also quite like
Sleep (although they're a bit hit and miss),
Fu Manchu (although they don't get the trippy stuff like Kyuss do), recently
Colour Haze have been getting a fair bit of play. More into the metal side there was an independent band
Camel of Doom whose last EP was excellent, although I thought the earlier stuff was... quite forgettable.
Queens of the Stone Age are, needless to say, excellent, and although they're quite different to the bulk of Kyuss' material, if you give a listen to
Demon Cleaner I think you'll find a similarity in style