Check out some YouTube videos. I've seen a pretty comprehensive one on the Premier and a somewhat less informative one on the M500. I decided on the M500 from Marina Pool & Spa. The M400 and M500 both have a counterrotating third brush, which has potential to clean pool surfaces better than the front and back alone. Along with some other Maytronics models, the "exhaust" water shoots straight up, which I believe helps keep the cleaner pressed to the surface of the floor or walls. The split front and rear drive system allows a "zero turn radius", which makes it pretty nimble. With the handle/floats properly configured, it also does a remarkable job at the waterline, although I take five minutes before running the M500 with a pool brush giving that problem area a quick brushing. Marina Pool & Spa has extraordinary prices, availability, and shipping. I had decided on the M400, as the M500 benefits over the M400 seemed unnecessary, at least to me. However, Marina's M500 price sold me on that one. I'm sure other less pricey Maytronics cleaners would do as well, but I've gotten into trouble too many times by trying to save a couple dollars...to which my wife will attest. Getting the "top of the line" also assured that my wife would be happy with the purchase.
One downside I've found--which may apply to other Maytronics devices--the Bluetooth remote and iPhone app combine to create an exceptionally mediocre remote control system. I have to hold the iPhone almost touching the M500 for an initial connection (every time), and have to be next to the pool for it to maintain its connection. The controls are clunky and non-intuitive. All in all, the Bluetooth remote and app are nearly useless. I just plug it in and press the go button on the power supply. When it finishes, I take it out and dump the two debris collectors. BTW, this monster is heavy, especially if your water line is far below the surface. And contrary to one person who posted here, I have no debris at all run out the bottom when taking the M500 out of the pool. There are vinyl boots at the collection slots that flop over and close the opening when out of the water (see pic)
, and for me they work well--even the first couple times I used it after having a terrible pressure side cleaner previously. The dirt, tiny pebbles, and just plain muck that came out of those collectors was really disgusting. After 6 or 8 cleanings, though, it's much less but never empty. And it's frankly amazing to see it climb the pool wall and actually stick the front brush above the waterline, seemingly defying gravity.
