For fermentation I would say Ranco dual stage (that auber looks real nice too). I have a Johnson digital and use it for fermentation...but I have to watch it closely depending on the weather outside. Does a great job cooling in the summer months, but in the winter it can get a little low. In that case, I just turn on the reptile heating pad. With that, the Johnson is always spot on and I have really enjoyed it, but a dual stage is ideal.