I was just there last month, and it seemed you don't really have a choice for lounges if you're leaving the Schengen Zone. My BA flight was out of the E gates (and FlightStats shows the AA flight there too), so I went to the Miro lounge, just after passport control. (Though it's a little perplexing that it says the Dali lounge - "operated on behalf of AA" - is not after passport control.)

In any case, the lounges there are operated by the airport itself, so it seems they'll all accept the same people into whichever lounge is in your departure zone. Since the place is brand spanking new, the woman at the desk didn't know how to admit someone to the club, so she had a big binder full of all the airlines' FF and lounge member cards (*A, OW, and ST).

As for the lounge I was in, there were a couple of computers for general use, and WiFi as well. The food selection was decent considering I was there at 6 am, and it looked like there was room for more food during meal times. I found the beverage selection to be quite nice - tons of little sodas and juices and waters plus a nicely stocked bar and wine selection (including cava). There were magazines and newspapers available, but only for in-lounge use. The furnishings were rather monochromatic, but there's a nice wrap-around glass wall that looks out onto the main hall of T1 and its included shopping mall.

Enjoy!