Should I buy this? This isn't from a retailer. It's off craigslist. It was supposedly donated to a benefit and is still new in the box. I wonder if I'm missing something (i.e. warranty issues with Maytronics if I can't show a receipt, etc). I don't really want another maytronics product, but I'm in a bit of a bind. This seems like a decent deal for $750 considering they are advertised at $1,000 it $950.