While Sha Tin isn't the worst place in HK by any means, I wouldn't recommend staying out there if OP wants to get a quick look at HK during the fourteen hours total he/she has in town. I'd imagine he/she would want to get a look at some skyscrapers, neon lights, etc.

That being said, at those hours and with a total amount of time of fourteen hours (at least three of which would probably be spent at the airport), I wouldn't put too much effort into seeing much of HK. It'd be a different story if it was a daytime layover but to get out of the airport, check into a hotel in town and then go to either Temple Street Market (which is rather unspectacular, IMO) or Lan Kwai Fong or Wan Chai for a drink at an expat bar seems a bit of a waste.