I switched to DL due to the AC MM fiasco. Beginning to wonder if OW and CX would have been better with the AMEX card.

The advantage of DL is AF/KL and getting to European destinations without having to transfer in LHR.

But both OW and ST have great Y+. I do not really need the upgrades if I get a more comfortable seat. I have my own AVOD and avoid the food anyway.