In Hong Kong we pay 15% tax.
In South Africa you'll pay :
Taxable income (R) Rates of tax
0 – 150 000 18% of each R1
150 001 – 235 000 R27 000 + 25% of the amount above R150 000
235 001 – 325 000 R48 250 + 30% of the amount above R235 000
325 001 – 455 000 R75 250 + 35% of the amount above R325 000
455 001 – 580 000 R120 750 + 38% of the amount above R455 000
580 001 and above R168 250 + 40% of the amount above R580 000
I'm too lazy to work the numbers but looks like you won't be that much better off with SAA. According to the ones in the know SA cost of living has also increased dramatically over the last 5/6 years.