Thanks for the comments. I know it's a tricky question. Sdsearch: I don't mind that much about redeeming miles, what is more important to me is the treatment and extra perks that status has. Lanpass cabin upgrades, it seem to me, are less likely to happen that AA (am I right?).
Being based in MSP I could switch to Delta but I don't like it from past experience and since I will return to Peru I'd like to stay OW that has LAN, with the biggest share of US-bound flights and AA, with the most seats in relation to Delta or UA.
The only thing that bothers me with AA is the age of their fleet.