I am looking into getting an auto pool cleaner. I am looking into the Dolphin models and the iRobot Mirra. I'm not sure which Dolphin model would be comparable to the iRobot, so maybe someone could help me there. Any thoughts on going with a Dolphin or the iRobot? I have a friend who has the iRobot and loves it. Our pool is in ground, vinyl liner, and 18,000 gallons. Any help or advice would be great.