Used an Iwaki before and they have a nice consistent hum, just lowered the bio-balls in the overflow to make a waterfall effect and cover up the pump noise. Can't do that with canisters, but didn't find it annoying loud.
Little Giants pumps are definitely noisier, but cheaper. Thats the only other pump I am using now.
Can try asking at http://www.reefcentral.com/ if you're not getting the advice you want.