For myself, as an Australian, Singapore is more attractive because of its proximity.
Hong Kong is also a global flight hub...in fact, compared to the US, most places in Asia are relatively close to each other.
If Singapore does have a tax advantage or a geographic advantage, it really can't be significant enough to be the reason you pick one versus the other.
If however I were doing business in China, Korea or Japan, Hong Kong would be a better base.
Singapore is a de facto single-party state with a strong prime minister. Is that good or bad? That depends on whether we're talking Aurelius or Mao. Having spent the better part of a week in Singapore this past summer, I can tell you that it was the only place on my itinerary where I thought, "I'd love to have a place here." (The other destinations were Thailand, Dubai, Abu Dhabi, and Ireland.) If I were to have a residence or business in Singapore, probably my biggest fear would be not government oppression, but rather the People's Action Party losing control, probably to the quasi-communist Workers' Party—i.e., a triumph of "democracy" over the highly effective government Singapore has today.
Singapore is consistently rated by the World Bank/International Finance Corporation as the number 1 country in the world to do business[1]. That covers the ease of starting a business, contract enforceability, getting credit, and other metrics that are necessary precursors to getting started.
Although China's rise has been the largest in absolute economic terms, Singapore has probably been the fastest.
1. http://www.doingbusiness.org/data/exploreeconomies/singapore...
It won't be like this forever. I think the autonomous government deadline is 50 years. When this happens, it won't be as "free" as it is now.
This is also only if the Chinese government doesn't go back on their word.
If you truly want a free country, go to Taiwan. Taipei is just as vibrant as HK.
The downside to Singapore is that they are authoritarians. Confucian capitalists, you might say. William Gibson famously called it "Disneyland with the Death Penalty" in a Wired article of that title.
Singapore is very pro-business.