Smoothie King is, quite literally, the king of smoothies, and with such an impressive reputation, it's only logical that they use one of the best blenders on the market — and they do. Their blender of choice is also The Quiet One by Vitamix, which underwent multiple quality tests before earning its place in all Smoothie King locations. According to their website, they not only tested its blending ability, but also "speed, sound, technology, ease of operation, durability, cost of ownership, and service after the sale," so you can rest assured that The Quiet One is one of the best heavy-duty commercial blenders you can find.