Reviews of pellet smokers vary by manufacturer and model, but they are generally good. Some units have thicker metal or more precise temperature controls than others, but all do a good job at smoking meats.
Pellet smokers use the same mechanism as pellet stoves to provide a constant feed of fuel pellets and maintain the temperature. Instead of the heat exchanger box, the heat and smoke from the pellets moves through the cooking box. While reviewers generally like the results from their pellet smokers, the quality of the pellets they use affect the finished product. Most owners use trial and error to determine the best fuel for their unit, and some choose different fuels depending on the foods they are cooking.