If your goal is earning AA miles, the only two advantages Citi AA has over SPG Amex is:

1) For places that don't accept Amex.
2) For churning.

Other than that, you're much better off with the SPG Amex.

As for whether you'll get more value from Starpoints by redeeming them for Starwood hotels or transferring them to AA with the 25% bonus (25k miles for every 20k Starpoints transferred), it really depends on the flights and hotels you need. If you're using AA miles for OneWorld RTW trips, premium cabins, and international travel, you'll likely get excellent value out of those AA miles. If you're using Starpoints for hotels in otherwise outrageously expensive locations (Europe, NYC, etc.), you'll likely get excellent value out of those Starpoints.