Have had this system running seven months, zero problems. I think it's awesome. Some guys think since it is based on temperature that if the air temp and water temp are the same, it won't work right, but I had at least six weeks last summer where the tank was slightly higher temp than my heater settings due to ambient air temp being higher and it never malfunctioned once.
I had it with an aqualifter but just switched to an Avast pump because I switched sumps that has a bigger return section and the aqualifter barely beat the ten minute timer, and would take too long if my ATO reservoir was less than 1/2 full.