Quietboard floor as an alternative to Plywood or Chipboard

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Anyone used 'Quietboard' panels as an alternative to Plywood or Chipboard for flooring purposes? Apparently this is quite a new product and contains cement/chipboard, and has been recommended for sound proof purposes on new floors. I was quite intrigued by it as it's meant to be waterproof and a good alternative to 25mm WBP Plywood I was going to use as a subfloor

http://www.customaudiodesigns.co.uk/soundproofing/cement_impregnated_boards.htm

For anyone thats used it - how rigid is it compared to plywood/chipboard, and would you recommend it for a bedroom floor that is going to have laminate flooring on top.