Aquabot Turbo or Tempo are fast and relatively cheap. I think they offer the most for the money.
Parts are readily available and with proper care you won't need any parts for years.
If you need repair and don't want to do it yourself, many swimming pool stores have on-site repair for your Aquabot.
Dolphin pool cleaners by Maytronics are also good machines.You can't get many replacement parts and if there is a problem with the motors, the robot MUST be sent out for repair. This could take many weeks.
