Magnetic window cleaners - any good?

I've just purchased a Magnetic Window Cleaner Deluxe for 32 mm double glazing Grey. I wanted to post a reply on my experience as I spent a long time looking at this product and saw a lot of reviews saying it was rubbish. I think this product is a useful addition for cleaning upstairs windows outside. It is not perfect and takes some practice before being competent with it. Firstly DO NOT put the two magnets together in the bucket of water as described. The magnets are so strong they just pull together and parting them takes a lot of determination. Second ensure water is soapy as the magnets need this to help them glide. Place the outside magnet against the window first with the sponge facing the direction you want to move first and then apply the inside magnet so they stick together. Always work from the top to the bottom of the window following the arrow on the magnets and move slowly. If you see the magnets beginning to part then move slower to allow the magnets to catch up to each other. When turning the magnet move even slower. This product DOES work but is tricky to use and I wouldn't use it for windows I can reach easily. I got mine for £20 and is better value for money than all other window cleaning brushes I've ever bought. Hope this review helps.