Last spring I finally decided to invest in a quality robotic vacuum. Based on TFP reviews I zeroed in on Maytronics Dolphin. So, to begin this is a report rather than a problem, and I hope that it may be helpful to others. I knew that a quality robot would not be cheap, but I was more concerned about the results of the vacuum and the quality/durability rather than the specific price. Last winter I was doing my research and was very interested in the M500. Fortunately, I had a dealer 15 minutes from me and they had a demo unit, which they were very helpful with. Once the pool was open I got the demo unit and used it for 3 days. It worked great, with one exception. I have an in pool table on a pedestal with seating and the distance between the seats and the pedestal was approximately the same width as the robot. The robot would eventually find its way to that table pedestal, get stuck and never back away. It did this 100% of the time. I called the dealer and they felt that there was no solution and that no robotic vacuum could handle this specific situation. I was thinking of what I could do to temporarily block that area, but my wife was not keen on this solution for an $1800 robot! Finally, I called Maytronics customer service and their recommendation was to try a Dolphin S300i. I was a bit surprised since the M500 was supposedly their top of the line, but they told me the search function in the S300i was newer and may handle the problem differently. My M500 dealer did not carry the S300i (apparently Maytronics has exclusive relationships for the sale of many of their robots), but 5 minutes away was a different dealer that sold the S300i. They had a new demo unit that had not even been out of the box and told me to keep it as long as I wanted! I only had it 3 days and to my amazement Maytronics was correct. The S300i would go to my pedestal problem area and momentarily try to get behind the table, but within 10 seconds it would turn around a leave! Maytronics customer service was correct! This almost sealed the deal for me, but I still wanted to fairly compare the features, quality of cleaning, etc. Both the M500 and S300i did an outstanding and comparable job cleaning the pool. I really like the modular design making repairs, when that time comes, much easier and hopefully less expensive (if out of warranty). So, I did purchase the S300i and this was my reasoning in my head to head demo comparison. Yes, the units are somewhat different with one big difference being that the M500 has two motors vs. one motor in the S300i, although for me the cleaning ability seemed the same. The big difference was the ability of the S300i to handle my table pedestal issue. Unfortuntately, I could not leave the M500 in my pool unattended and expect that it would finish its cleaning cycle since it got stuck 100% of the time. I really liked the single S300i basket rather than the two smaller M500 baskets. The single basket is quicker to clean (which I do after every use) and should handle leaves better this fall (but, I could test this). The S300i is lighter, probably due to the single motor, which my wife really appreciates. Don't underestimate bending over to lift the robot out of the pool if you are standing on the decking! Both units look pretty similar and come with a cart and the cart is quite handy. The anti-tangle device on the cord of both units works very well. Finally, the phone app works fine, but honestly I don't use it that often. After about 3 months of using the S300i I could not be happier and I consider this one of the best purchases I have made for our pool. The pool is sparkling clean and it takes just minutes to toss it in the pool and to clean the filters when done. No, it isn't cheap, but I was tired of the manual cleaning. Both of these models are not to be sold on-line, but I know that it is possible to find them. Maytronics states that the warranty is void if you buy it on line, obviously to protect their dealers. I decided to buy from my local dealer since they were very nice in loaning a demo unit. They also repair locally, if needed, and provide a loaner during the repair. I paid $1300 for the S300i and the M500 was $1800, so that was another factor. Both had a $125 rebate at that time and Maytronics was very fast at sending me a check (less than 30 days). In summary, this is my experience and thought it may be helpful to others. I know that M500 owners are very happy with their robot and experience as well. Honestly, if I would not have had the table pedestal problem with the M500 demo unit and had not called Maytronics customer service, I likely would have simply bought the M500. Both units seems to be excellent at cleaning and of high quality! I hope that this does not result in a debate of which unit is better, since I think both are excellent. I find TFP excellent for recommendations and I hope that my experience will be helpful to others looking for a robotic vacuum.
