Good tailor, but not as good as my favorite - Rajawongse in Bangkok. These guys are a well oiled machine and sometimes I felt just like a cog. They made some nice trousers ($1050 each).
Extremely variable quality. Sometimes top notch, other times rubbish. Haggle and be firm on what you want. Don't let "Sam" fob you off with the "trust me, I'm telling you" line.
Sam's is the real deal and prob the most famous in HK. My suit, and shirts are perfect. The other guys are going substitute garbage polyester blends. It was an amazing experience. Ask for Roshan.
Hong Kong's legendary Sam's Tailor is famous world-wide for its unquestioned reputation for quality and discretion - and a clientele seemingly culled from the pages of the International Who's Who.