The Matty hoverboard was a complete and utter failure. It is not accurate in anyway, shape or form. Even Bob Gale has disavowed any relation to it and has even apologized for how it turned out.
The Clock88 board was made by a "now banned" member here named Grant. He had YEARS of research put into these boards. He tracked down every reference, materials, measurements of every hoverboard made for the movie. He made only about 10 boards and then screwed people over, not sending their boards. I was lucky to have got one of the first 10 boards. These have the exact lenticular patterns, velcro, magnets, battery pack, and vinyl stickers. It is 99.9% accurate. It's gorgeous.