I have two of the 1200's, they are nearly silent. I say nearly as all you can hear is the hummingÂ

. Not loude at all and I tried them on my Hydor wave maker, no clicking sound and they start in the correct direction evertime. Cant say anything on long term as I only ran them for two days when water testing my plumbing and tank.
They are a little bulky but I found that there modular shape blends in well enough...