I use SPG with the intention to transfer AA though I never have had to. The Citi AA card is well worth it for the 10% back on redemptions. Other than that, I am a big fan of transferable cards (UR/MR) and cash back cards. There are times where I do use Avios for short expensive AA flights but my EXP status helps with that (get MCE, free snack/drink in coach). I also have the Amex Platinum for lounge access (which also gets me into Delta and Alaska).