Quiet ones are cheaper but imo excellent. I looked into three pumps mainly. A pondmaster, which for 80 bucks pumped 250 gph. I looked into a catalina (which is crap, I know from experience) that was 450 gph for 55 dollars. The quiet one (the one I purchased...which I knew from experience before was a pretty good brand) was 581 gph and 45 dollars.
Why? I don't quite know...
The most expensive one pumped less than half for twice as much. Who knows%%