I think any Agricultural Civ, whether played by the A1 or human seems to dominate earlier. So with the poll options its difficult to pin point just one best A1 Civ out of Dutch, Mayan, Incan, Sumerian or Aztecs. Out of these five I've noticed, in my games, the A1 doesn't seem to play the Mayans as well as they do with the other four. The most difficult wars I've had have been against the Dutch, and surprisingly the Incan, despite their poor UU.