I’ve yet to see a keyboard that beats this one at least at one category that mater in keyboards, sound, feeling, mechanics or endurance. This model has it all. However, the original produced by IBM is not in production anymore, but rest assured, since a company named Unicomp purchased the rights and still produces this famous Model M, along with other cool keyboards. However, since the keyboards are so enduring and high quality, their business does not run that well and to quote from Wikipedia article on IBM Model M:
Unicomp has had difficulty making them profitable because they rarely break, and most retailers will not stock such an expensive keyboard.