So far so good. The unit has been running 3 hours a day and my pool is spotless. Since my pool is small one hour a day is probably enough but I have my water features running in the evening for 3 hours and the cleaner works when the auxillery pump is on. It even climbs the steps! (most of them. The top step just isn,t deep enough under water.) The unit is much simpler in design than either a Polaris or Letro pressure side cleaner (I won't even get into the Hayward Phantom or Viper). The Polaris units work well but there are a lot of parts that need replacing on a regular basis. The Mars really is amazing in how it is made. No gears, just propellers that are water driven. They are a bit cheaper than the Polaris units and Zodiac probably used a lot of what it knows about the Polaris units when they designed the Mars HP. (Polaris is owned by Zodiac.) All in all I am extremely pleased with the unit. We shall see if I am still pleased a year or two down the line. The early units only lasted a year or two and then started falling apart but they have been significantly redesigned, right on down to the scrubber on the whip tail.