You have to look at the flow/head tables. 1/2 HP vs 1.5 HP doesn't necessarily mean ANYTHING, because of all the games they play with horsepower ratings.

One of the things I've dreamed about, is setting up a pair 'Consumer Reports' type test pools, to test various pumps, valves and filters and then publishing the results. Doing so would provide objective data about that equipment that is not currently available.