I've had great success with the Tunze stream line (6060, 6080, 6100, 6105, and 6065) over time. Always quiet and reliable.
I have tried a few version of th MP-40 and the noise has alwasy been an issue for me too. I did just add a MP-40wES and found it quiet... but ONLY by running it at max of 80% would that occur. Otherwise, motor noise and vibration was unaccceptable.
I am using it with a 6105 and a 6065; it's the best of both worlds!
PS Both companies have just wonderful customer service.... best in class!