I currently have one Koenders windmill which is very similar to the OWS and one American Eagle windmill. The American Eagle truly does put out a much bigger VOLUME of air. More volume is going to move more water.
On top of that, the American Eagle is built like an absolute tank. Much Much more heavy duty. My Koenders had a failure in the very first season and had to be sent back for warranty. Tipping the tower up and down to deal with problems and maintenance is not fun, trust me. Mine failed and had to be dealt with when there was already snow on the ground.
The only draw back to the Eagle is pressure. It can only aerate down to 16' or so IIRC.
