Is the early morning (around 7 AM) flight not available? Check it out.
Also keep in mind the cost of parking. At ACY it's $4.25 a day. At PHL it's a lot more, but I'm not sure how much. In addition, ACY is a very small airport, I think only 6 gates. Not much walking, can't really get lost, not too crowded, no massive security lines, parking is very close to the terminal, etc.
As others have said before me, THE ONLY difference between American and Spirit is that when you are leaving your WDW resort, with American you won't have to get your luggage to the airport with you, and with Spirit you will. That's all, just the actual handling of your luggage between the resort and the airport on your way home. Think about it -- every time, every place you fly you have to handle your won luggage and don't even think twice about it.
If you fly Spirit, you can get a Bell Services CM to help you with your luggage towards the bus, the driver himself will load it onto the bus. When you get to MCO, the driver unloads the luggage, ans then you could do what I did and snag a skycap who will handle your luggage for you (in exchange for a nice tip) all the way from the bus to your airline ticket/check-in counter. So even though I had to be responsible for my luggage on the way back to the airport, I never actually lugged a single bag (Bell Services picked it up from my room and stored it, Bell Services got it out of storage and left it on a cart for me when I was ready, the driver loaded it, etc.). And check this out -- I tried tipping the Bell Services CM and she refused, TWICE. My last little slice of Disney ....
-- Eric
