I was left a Harris AGP pump from the prior home owners. I swapped it in this year as the other pump's basket cover was severely yellowed and you could not see through it. As well the base was disintegrating to the point it had one screw holding it onto the base.
We ran one season on the old pump (Hayward 1 hp I believe) and a month or so on the new one (Harris 1.5 hp) so I have not seen a utility bill. However, didn't have a good test kit, had an algae bloom and when I replaced the filter valve I didn't also replace the short piece of PVC that connected it to the internal piping so I had the pump going 24/7 for 10 days. Once that got fixed, pool cleared up quickly.
Filter PSI went up 3-5 psi between the old 1 hp and new 1.5 hp.
I was recently concerned about the flow difference between the 1 hp and 1.5 hp but the Harris manual says that with 1.5" plumbing the max flow is 45 GPM. I'd prefer this to be lower but only way to do that would be to put in some flow restrictions. Would have been nice if we were left with the same HP pump as what was in use but it means it wasn't something I had to buy...