I love them, on a hardtail i think they are a brilliant idea, more comfort and better grip on the rear as the tyre keeps in contact with the ground better.
I think once you put them on a full suspension bike the advantages become smaller.
Still not great in proper mud thought but amazing on rough rooty hard ground, but I think this is a tyre thing at the moment, i have 3.0 nics and they are pretty good want to try a more aggressive 2.8 minion or something like that. The tyres aren’t wuite there yet, same as when 29er tyres were new you couldn’t get anything other than XC tyres and gradually got better and so will plus