I'm planning a trip to South America sometime in Feb/Mar 2014 on AS miles. Any advice on which is the best partner(s) to get there in J or F? By "best" I mean most comfortable and/or fun and enjoyable. Lets assume I'm flexible/lucky enough to find availability for the carriers I want. We would originate in BOS, but could easily reposition to JFK, or possibly even MIA. I see that AA is the only partner that has an F cabin to deep south America. I have heard good things about LAs J seat, but mixed reviews about the service. I know next to nothing about AM, but a stopover in MEX could be interesting. I'm currently considering an attempt to try to mix and match the 787s on AM and LA, but I'm not sure how those would compare with AAs F service.