Wing Shing Photo and Man Shing Photo in Mongkok are pretty decent. It's the only place I've ever actually recieved 'decent' service.
Canon will beat any compact camera hands down overall. I used to sell and test compacts and Canon beat up on every other brand in every low-light test we did. They are the fastest by a HUGE margin. Start up time, etc.
Nikon has slowly declined, Panasonic is a laugh, Fuji -Casio etc. etc. are all junk.
Sure Canon is the biggest company and can buy good reviews with all their money, but they can also buy better technology than every other manufacturer.
Anything with a Digic III processor will kick***