Not sure about the value for money part, It seems that is subjective and depends on each person
Standard stores for rackets of course is Marathon ,Giga sports and sports sectionsmof Jusco, Sogo etc, especially when they have discounts and sales
There is racket specialist shop in Causeway Bay, down Causway Road, opp Victoria Park, out in the corner where Sugar street joins Causway Road, cant give better directions than that - sorry
also saw some recent ads for
www.racketshop.com.hk