I have run the 45MPHP10 model since October 2016. Lately, I have been on the cusp of going SWG. I seemingly burn through a lot of chlorine in the summer here in Phoenix. Last year, the pool consumed $241 worth of chlorine, which was a total of 36 gallons of 10%. That may be on par with a decent pool seaon; I don't know. All in all, in order to fight the solar burn-off, the Stenner runs 4x a day at 15 minutes.
It probably was mentioned before, but I will state it again: a Stenner pump or other means of chlorine injection still needs to be maintained. Being that I only have experience with a Stenner pump, I will say that it has been anything but headache-free. You must keep your eye on it! Set a calendar reminder on your phone to perform periodic and preventative maintenance. Of course, AZ is brutally hot in the summer and the sun is intense, but most of my failures below occurred in the "cool" season.
Over the course of ownership, I have replaced countless tubes (one of which downright split causing a disasterous low-chlorine situation in full Phoenix sun), countless ferrules, several duckbills, brittle sections of tubing (caused by the chlorine, not the sun), just replaced the roller head the other day, and so on. I've found that the tubes fail inconsistently. It may be a year, it may be 6 months. It could be 4 months. The failures may be in the form of split tubes or hardened tubes that may allow back-pressure (failed duckbill) to put water into the chlorine tank.
So all in all, if you go Stenner, keep your eye on the Dang thing!