I really like the Ecotech MP40s. But they are pricy.
Part of it depends on what kind of system you are running. I run an SPS dominant system so I have quite a bit of flow (Over 50 times), Originally, I thought that the more slow moving fish might have problems with powerheads but even the slowest fish never had a problem. In facts, many of them surf the powerhead (they swim up to the side of the powerhead and then right into the blast so they get blown across the tank WHEEEEEE.
I have found that when I have gone cheap, the powerheads die after a year or two. Going more expensive and they last, and last, and last.