maxis or hagen(aquaclear only though)
maxis for price and reliability and AC's for reliability and funtionability(though the maxis are right behind them, IMO)
Definitely avoid rios, my major issue with them, is not that they are bad, but when they die, they can be hazardous time bombs in a tank.
and the Zoomeds, are nice in theory, but are short lived in sw tanks
the others, like penguins, and Hagen(not AquaClears) work, but are not worht the money saved, IMO. They just do not seem to pump enough fo rmy wants.