The AA executive mastercard was running a pretty good sign up bonus that would make the card really worth it...I think it was 75k miles on sign up. Not sure if that's still around.
Keep in mind the Citi card is just Admirals access, not membership. You have to be flying AA within 12 or 24 hours of your lounge access. Priority pass comes with this too and it's great for international lounge access (flying abroad) but honestly, I have rarely used mine domestically (I use AMEX plat, so use Centurion when I can).
Also, this post may be moved, not sure this is the correct location but I'll leave that to the powers that be to determine.