I've heard a lot of good things about Emerald Coast, but I would be careful on how you answer the question if asked, "Did you do formal interview prep." Emerald Coast will tell you to deny it. I believe that if asked, the interview team already suspects it of you anyway. If you deny it and they question your integrity, then I'd say you've probably just lessened your chances a lot. I was asked that question during my SWA interview and I answered honestly (Minimal interview experience, wanted to come across as professional as possible, yada yada.)
I echo what Scrapdog said .. I would highly recommend interview prep!! I have a military background, so it paid dividends for me. Best of luck.
Patch