I live in Hong Kong, and can verify that it is absolutely a technologist's paradise and an extremely easy place to move around in.
Phones are incredibly cheap; the cheapest functional Android knockoff smartphones will run you about $50-80 (all prices in USD for simplicity), maybe less if you get it in Kowloon. "Burner"-style phones can be as low as $8. SIM cards are essentially free (usually about $8-10 deposit on the card) and minutes are as lower than $0.01 each[1]. Data is about $5/GB prepaid. All cash, no credit cards, no checks. You don't even have to give them your name.
Coverage is completely universal here because the density is absurd. It's a cell phone carrier's dream; one tower can potentially reach nearly a million people. Taxi drivers here regularly have half a dozen cell phones in their cars. One for personal use, one for work, one for less savory work... who knows, there is always a lot going on, especially in relation to gambling.
Additionally, the broadband is great (and cheap) - I regularly get as much as 250mbps or more to the US from my home connection. I can say with confidence that I browse US sites more quickly from here than I could from my home connection when I lived in the states. The ping is of course higher but it is not as bad as you'd think (150-180ms).
There are great technology centers like Cyberport[2] that will rent you a desk or tiny office with gigabit internet for very little money.
It is easy to disappear in HK because it is so dense. While housing is not cheap it is available and some landlords will take cash. Being white earns you stares here, it is well known that the Chinese suffer from the same problem we do; it is difficult to tell white people apart, much like we may find it difficult to tell some ethnic Chinese apart. I am speculating but it could be used to his advantage: with a hairstyle change and contact lenses it would be difficult for a US citizen to identify Snowden, going only on the news photos. It would be even harder for a foreigner. That is, if the novelty of seeing a young nerdy white man doesn't arouse suspicion alone.
Members of the expat community have been setting up rallies for Snowden and they have been getting decent attendance. The South China Morning Post has been very favorable in their framing of his actions. I think the populace here is very sympathetic to his plight.
As for the legal system, I can't comment; I just work here, man.
[1] Keep in mind, prices are in HKD - 1USD = 7.76 HKD. http://one2free.hkcsl.com/jsp/prepaid_sim_card/o2f_local_pre...
[2] http://www.cyberport.hk/en