Apparently he can't clean corners because of the round pads. But I've seen a lot of people complain that he doesn't stand up when told to. The trick is to slightly dampen both pads with just a few sprays of aerosol window cleaner. After all, if the pads are dry, it will not climb into the window. Otherwise everything seems to be working fine so far. Had it for about a month and used it on five or six windows.