Just here in Antigua enjoying the sights and wanted to share what I have experienced on money matters. I brought a mix of TCs, cash, credit card, and ATM card.
Posted retail cash exchange rates are about 8.17-8.20 Q per US dollar. My ATM card has been netting me about 8.27-8.29 Q per dollar. Over the course of the $800 I have exchanged, I've received about 80 Q more than a straight cash exchange, which is enough for a good meal for the two of us.
Finding and using ATMs has been no problem and they all appear to be well serviced and no one has been out of money. Of course, we have stuck to the ATMs in the more touristy/safe places.
Hope this info helps someone.