I am looking for some advice on miles accumulation on Emirates or its partners.

I typically fly from North America to India about 5 times a year in business class. So far I have been doing the journey on Cathay and accumulating miles on their Asia Miles / Marco Polo program. Its been good as its given me One World status which helps with domestic travel in US. Also, Cathay has been fairly liberal with complementary upgrades to First on more than one occasion.

Recently with Emirates launch of SFO service, their connections and fares are better than Cathay. I am trying to figure out if I should join Skywards or accumulate points on one of their partners (I'd probably go with United with respect to partners).

Any thoughts?