When flying within Asia, should I sign up for an account with ie. Cathay or Singapore Airlines, or should I stick to my CO/ AA?

I will be flying more from the US to destinations like Singapore- Japan and Vietnam. That include a lot more flying between the local destinations: Singapore - Japan - Vietnam.
When would I benefit from signing up for a local program? And how would I ensure that I get 100% miles with the local airlines credited to my CO/ AA account?

Their link seem to be blank when it comes to AA; AA Cathay

http://www.aa.com/i18n/AAdvantage/pa...hayPacific.jsp
Class of Service
Purchased Fares
Booked In:
Mileage Accrual Percentage
Elite Qualifying Points Per Base Mile Earned
First Class
A, F
100% + 50% bonus
1.50
Business Class
C, D, I, J
100% + 25% bonus
1.50
Full Fare Economy Class
B, Y
100%
1.50
Discount Economy Class
H
100%
1.00

I have always found the Asian Airlines to be less generous than AA/UA for mileage.
AFAIK, all *A partners allow mileage accrual on each other.

http://www.continental.com/CMS/en-US...spx?ItemId=304

Class of Service Purchased Fare Class Base Miles Elite Qualification Miles Elite Qualification Points
Suites R 150% 150% 1.5
First Class F, P, A 150% 150% 1.5
Business Class Z, C, D, J 125% 150% 1.5
Full Fare Economy Class S, Y 100% 150% 1.5
Economy Class B, E, M, H, W, U, L, K 100% 100% 1
All other fare classes do not accrue mileage. Continental Airlines and Singapore Airlines reserve the right to change the eligible fare classes at any time without notice.

I credit most of my long haul flights on AA and use CX for most of the intra-asia flights. Asiamiles isn't the greatest of programs, but the redemptions can be gamed for certain distances within Asia.

As long as most of your travel doesn't originate in HK, you really won't be price gouged.