I would look at Southwest. More flights and if you fly Busn Select, you can change flights without any fees. Some good rewards, again espec if you fly at the slightly higher fares. If you have a companion who would fly with you 4+ times a year, the Comp. Pass is a great option.

Of course, in Dallas it depends on how close Love field is vs. DFW.

And, starting in 2013 (I think) the Love Field restrictions come off and there will be more flight options.