Bought this as a replacement for my black and decker robot vacuum (which work awesome, but broke in 6 months twice). Shortly after I tried the robot... total waste of money, I returned it within 30 days. I bought this RV 750 model on the Air Force Base last Christmas. Unfortunately by the next Summer it was making noise that I can only describe as laughing hyenas. Very disappointed as it was the best cleaner out of the three. Guess I'll try another brand any suggestions?