I am a Brit living in Macau. Income tax will be abolished altogether next year. You can live here as long as you like, so long as you visit HK (or some other country) once every 6 months.
Also, if you spend HK$1m on a property, you can apply for residency - but the advantage of that is really if you want to work doing something else here.
BTW, the real advantage of living here is the cost of living is 1/2 that of HK (also, many expats have okay 3 bed appartments with decent views costing HK$5,000-6,000 per month.
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