I simply cannot understand why they cost so much. I won one in a raffle and have used it twice. It's basically lightweight plastic crap which tries to reinvent the wheel and there is still water all over the floor. I prefer my trusty squeegee and a bowl of water.
For cleaning windows, I cant really comment on as I also don't use it for that. We purchased to get rid condensation on bottom of windows in winter and for drying up the bathroom after showering. My dd literally swamps the bathroom with moisture/steam. Use it to suck water off tiles walls and sometimes ceiling. Would not be without it for that, have killed two already but it gets a lot of work! Helps to prevent mould.