Both AA and DL fly to Santiago. CO only uses the DL codeshare. Both airlines fly the 767-300. DL has BE service. AA service is a comfortable Biz class seat also. I haven't flown Lan in F just Y and I believe they are the best airline based in SA. DL BE is OK not as comfortable as CO. I'd probably choose DL simply because I'd know what I was getting. Personal Screen, OK food, and a somewhat comfortable seat.