I have the Diagnostic and so far I've had no problems(well, one-it did stop in the middle of a cleaning once. It turned out the GFI tripped on the outlet). I have only had it about 3 weeks though. Too early to tell. I am pleased with how it cleans the water line. It reaches the top and then scrubs sideways for about 2 feet before reversing down. I hadn't expected that.
I have read very good reviews about the Blue Diamond and so many here love their Poolbusters one would hope the same for the Pearl.
One thing I liked about the Pearl over the Dolphin is, from what I could see online, it looks like the brush and treads are softer and flatter. I have a vinyl pool and the Pearl looks less damaging to me, but I couldn't afford to be a guinea pig since no one here had used it before so I went with the Dolphin.
Please do write a review after you've used it a while.
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