I've had my XP3 for around a year now. It has been a good, efficient, cost-effective filter. But, in all honesty, I wish mine were a bit quieter. My house in Florida is a very open floor plan, and in the evenings when I'm getting ready for bed, I can hear the humming for a couple rooms away. I've tried wrapping a towel around it, and it does sit inside a closed stand (on the front anyway). But, it has got a hum....and I'm not the most sensitive hearer in the world...though perhaps that is a frequency I'm sensitive to?!?
I still recommend the Rena, but at times I think about trying an Eheim to see if it'll be quieter. I wonder if I could order a new impeller or such to see if it might quiet it down some??
46g bf, XP3 w/ vertical spray bar, CO2 w/ SMS122 & diffuser,100% Flourite, 96w+55w cf AHS, AGA Member