Just for the record -- as far as I can tell, Mark (mas985) has done more research, and is more knowledgeable on pool pump performance, than anyone else who is speaking publicly in the English speaking segments of the Internet. This probably means, he knows more about the operational and practical aspects residential pool pump performance than anyone else in the world.

I don't doubt that some mechanical engineers employed by Hayward or Pentair may know more about design and assembly than he does -- I've been greatly helped by some of those guys in years past -- but in my experience they have a somewhat limited perspective, and certainly cannot speak candidly about performance across brands.