Not been there for a few years, but the food certainly used to be great in the Wong Kei, and I've had some really funny "lack of service" moments in there. May well have changed by now, but back in the day I often wondered how you'd actually get out from the 5th floor if there were a fire, thoughWong Keys at the very end. Renowned for its lack of customer service it's a cash only establishment and the food is awesome!
If you are looking for great Cantonese food try the following Chinese restaurants in Queensway rather than Soho/Chinatown.
1. Mandarin Kitchen (world famous lobster noodles - ask for the ginger sauce version)
2. Royal China (great dim sum - but limited selection), also at Baker Street.
3. Four Seasons (great/world famous roast duck)