I think the pumps are great, but they do require periodic maintenance (as do most of our reef equipment). When they get dirty, they get louder. I usually take one off-line at night to soak in vinegar to remove calcium deposits, then rinse and put it back on-line in the morning.
I recommend purchasing the maintenance kit from Ecotech, so you'll have it ready when you need it. One of my MP40s had a drive shaft fail, and I wish I had the parts ready for a quick replacement, especially since most LFS don't carry parts.