Dadant smokers are about the only ones I've ever used. I have one from someone else, but never used it. The bellows spring is too stiff. The Mann Lake smokers have that Yellow Bellows and wing nuts too, I believe. I have heard poor reports on them.
It would be interesting to hear of other brands and what they are like. I don't see how there can be all that much a difference, but that's probably me.