All depend on what you expect. If you expect to earn mileage, Citibank Cathay Visa or Bank of East Asia VISA are recommended. If you expect to have attractive become gift, HBSC VISA is recommended. If you expect to earn more bonus point to redeem gifts, HBSC, China Bank and Bank of East Asia VISA are recommended.
They often have promotions which I always have extra cashs/coupons redeemed. In addition, you can use it to settle the 水電煤,etc which you will speedup your earning of bonus points.
HSBC has the most variety of gift to redeem from, but it is only $1=1point. HSBC can settle bills of quite a no. of companies.
Citibank can earn double points if you are citigold, but no. of redeem gift is a bit less than HSBC. but it can settle town gas, china power etc with credit card autopay.
For AE, the redeem gift are mostly travel products eg travel package.