Instruct: Classify Amazon reviews into positive or negative sentiment
Query: inconsistant quality

I bought two of these and one of them is indeed whisper quiet but the other one is much louder. It is nearly as loud as my old chain drive. It functions however so I'm not sure if I could return it, and I had it all put together and hung from the ceiling by the time I first heard it working. That unit also over-heated while tweaking the safety adjustments, the manual says to run it through a full cycle after each adjustment. It shut down with an overheated diagnostic LED warning after 6 or 7 concurrent up or downs. The door is correctly balanced with brand new extension springs, and I ran both units with the doors released to hear just the motors. One is definitely 3 or 4 times louder. Also one of the clickers didn't work, but it's not a big deal because each unit came with 2 so I still have 1 extra (two single doors on garage).