We are using SW for the 1st time and I am not too keen on the seating. For JetBlue is just too expensive. We used them on our 1st 3 trips because they were so cheap, but now they are one of the most expensive out of our airport.
Edit: I forgot to add that we did pay for priority seating (or what ever it is called) do that we should be in one of the 1st groups to board.
Which airport do you fly out of? After I already booked our flight I started looking around at other flights and couldn't believe the vast difference in prices from airport to airport (even when the airports were relatively close). It turns out I could have saved about 13 dollars a ticket it I had flown out the day before. (Tuesday rather than Wednesday) Of course when I was booking everything I didn't realize how much flexibility I had with the Disney reservations. I know so much more after reading this site. I was more the type that booked the dates at the resort, then grabbed the plane before the seats filled up.
I did look at other airlines and JetBlue was pretty much the cheapest out of Newark when we are going down. There were a couple of flights cheaper, but they had stops and would have wasted the entire day in travel. Some left at 6:30am and didn't get in until almost 6 at night. At that point I might as well have taken the train, saved money and not needed a pat down

Let me know how SW goes when the time comes. Is it a direct flight?