Having read a lot of positive reviews of the vacuum cleaner I eventually persuaded my husband to buy one ( we both have bad knees and I thought it would help) I was very happy with it at first and then reliability and problems arose,they take quite a lot of maintenance and the battery life is short,I replaced ours after 6 months (£50) and when the on board navigation went wrong I contacted Irobot but to no avail as I had purchased it on Ebay from a dealer who said a 12 months warranty with Irobot was with it,Irobot said that they only honour warranties from approved retailers,I can only presume the people who review these vacuums have only just or recently purchased them and have no idea of the long term ownership problems .Two people I know have encountered similar problems.