I booked our flights this for this past June in early December last year. I kept an eye on the prices and they never went any lower, so if you find a price you like, I would go for it. I did see lower fares for less desirable times, but I am pretty picky about the times I want. By our trip, fares had climbed over $350 for almost 2 months prior.
We had a good experience on Airtran, and I will fly them again if the price is right.