"It's a quiet DC motor fan at an AC motor price, trading build quality for better performance."
The '20dB Quiet' spec refers *only* to the lowest of five speeds. While this is legitimately quiet for sleeping, higher speeds will produce noticeable noise from air turbulence, just like any other fan.
This fan is for someone who needs very quiet air circulation for a bedroom or office and is sensitive to the low-frequency hum of typical AC motors. The energy efficiency is a real, if small, cost-saving benefit for users who run a fan constantly.
A buyer looking for maximum durability should skip this. The plastic construction and adjustable stand are not designed for high-traffic areas or workshops. Anyone needing a powerful blast of air to cool a large, hot space should consider a simpler, more powerful (and louder) industrial fan.