The easiest way to compare pump efficiencies is to look at each pump's head curve. You will notice that for a given head, the Northstar will have the highest flow of any of the pumps listed which also means the shortest run time for a given turnover. The extra money spent on the Northstar will probably pay for itself in the first year.
Also, for an 8 hour turnover, you only need 80 GPM so 1 1/2 HP may be too much pump. 80 GPM for the Northstar is over 70 feet of head which is very unlikely if you are using at least 2" pipes.
To learn more about pumps, head, turnover and other issues, I recommend this site as a primer.
http://poolplaza.com/pool-pump-sizing-2.shtml
http://www.poolplaza.com/pump-ratings.shtml
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