I think it depends on your circumstances. I use UA's MP because they have some of the best redemption values, give 100% EQM for SQ qualifying flights, and have good elite benefits. I keep a US based credit card for dollar purchases, so get MP points on that. There are no taxes or fuel surcharges, even when redeeming on SQ, and I generally find good availability (others have reported problems).

Asiana is good for more infrequent fliers, because only needing 40K miles to qualify for gold status for two years, as reported above. ANA has a family plan where you can consolidate miles, but I think that the earning rate may be limited on some SQ flights.

The favorite European *A operator used to be BMI because of rich opportunities for bonus points. But since their acquisition by LH, most people expect a consolidation into M&M (might already have happened- I don't pay much attention to the European operators). I believe there is a *A operator that gives elite bonus miles when flying other *A carriers- might be BMI.

To me, the biggest disadvantage to flying SQ but accumulating your miles on another *A program is that you give up the 25% elite bonus miles. However, I fly UA enough (~1 a year transpacific) that the 100% bonus miles there make up for it- and I feel the better redemption values and lack of fuel surcharges and taxes also help.

There are many threads on this in the Star Alliance forum, and you can post your own details here for advice- http://www.flyertalk.com/forum/star-...st-here-7.html