Yes, your location will be a major deciding factor. If, for example you live in Tai Tam, you'll get much more out of the American Club. The AMC (Aberdeen Marina Club) has more facilities (better playrooms, more restaurants, skating rink, pool that is open in the winter etc.). The American Club does not allow helpers except to supervise children in the playroom - which is an attraction for some people, it puts others right off (a neighbour of ours never uses her American Club membership because she has 1 year old twins and says that they are impossible to manage on her own). The American Club also has a city club, which is apparently useful for corporate entertaining.
Personally, I prefer the decor and location of the American Club, but find the facilities and classes at the AMC much better for the children. You will be happy whichever one you choose.