I have the whole range of their pumps running in my systems.
This includes the
OR1200 - 18w
OR2500 (sump pump on my 120G system) - 38w
OR3500 (original sump pump on my 300G system)
and the OR6500. (new pump on above) - 95w
The latter, a big 6500lph pump did hum a bit when new, but is dead silent now, once it slimed up a bit. I went bigger on my main reef tank because I run 2 bleed offs to a fuge and frag tank. This together with a 5ft lift, I was loosing too much flow with the smaller OR3500.
Their pumps are relatively energy efficient, a OR3500 only consumes 65w.
One tip, when installing, I prefer to use a piece of flexible PVC piping when joining pump to hard pipework. Also good to insert a small rubber shim wherever hard piping touches glasswork, this also reduces noise and vibration.