Take it. That's a good fare. You might be able to get better, but in August, I'm not sure. If you can live with it, take it.
blanq says it's high. Maybe. Sometimes Airtran runs a sale, but it's not always valid for all days of the week. Also, Airtran is notorious for changing flight times A LOT. Sure, they have a non-stop, but it typically doesn't leave until mid-late morning. Are you okay with that? If so, maybe Airtran is for you.
For NWA, non-stop, if the times are right, $237 may be a little high. And by little, I am talking like $10-$20. Is that a goodly amount if you are travelling with a family? Sure. But if you are happy with the times, the non-stop and can live with the fare, I'd just take it. But you are also talking to someone who will take a fare like this and call it good enough rather than driving myself rabid trying to save another $10-$20.
JMHO.