My Gaerne boots were carpet slipper comfy from day one, but I think this can be a disadvantage as despite looking after them they only lasted me a year before breaking down. Having said that, considering the conditions these boots are continually exposed to, that really isn't too bad.
My latest pair are Novogar - which took more breaking in and appeared stiffer from new, but now they are just as comfy and seem to be more resilient and harder wearing than the Gaernes.