My humble advice is don't bother with the HK$50 unlimited travel
because it can only be used on their MTR. Unless you are going to
really faraway places like Lantau Island in the west then Sai Kung
in the east. Even so, you might not even exceed HK$50 unless you go
to Disneyland Station to take pictures. There, you will get to see
the barrier on the station platform that Singapore is going to
build. 
A lot of factory outlets (Nike, Levi, Espirit, Giordano, New
Balance, Addidas etc.) are concentrated in the shopping centre at
Tung Chung in Lantau Island.
