Plus, do not forget that most NON-USA frequent flyer programmes are still miles based. I find the Japanese programmes to be very good if you do not care about status. Plus there are sweet spots in the Czech OK programme and the MEA programme.

Personally, I fly with Alaska Airlines and its partners (Qantas, Fiji Airways, Emirates, Cathay Pacific and Singapore Airlines and they all fly into Adelaide, Australia). Most of my Star Alliance flights are credited to ANA. Most of my OneWorld flights are credited to Japan Airlines. I have dumped the big 3 USA airlines for mileage earning opportunities but if you like Status, then a case can still be made for Status runs on the big 3. For me, status is not important as I prefer to stay away from airline lounges and USA domestic flights are not usually over 5 hours long anyway. I can do economy for that long - np.

It depends on where you live, your travel routes and of course your travel redemption goals.