I found ticket prices in the sub $300 range, for December. Too bad their schedule doesn't go into 2016, yet. I'm still working on a February trip.

As a US Air/AA frequent flyer, I certainly hope this competition drives down prices. I remember when Southwest setup a Philly hub a couple years ago. I had hoped for the same, but SW quickly exited the market citing Philadelphia's unfriendly business rules and taxes.