JetBlue is my airline of choice. I love the amenities...nice, comfy leather seats, those personal TV's for each seat. You get the seat you want, well, as long as it's available to get when you book, but there is no 'cattle call' like you have with SW.
Granted, you can't book as far in advance as I was used to. But, the upside of that is that JB stays with the schedule pretty much. They don't change/cancel flights several times before your travel date like other carriers.
There is a $35 change fee (I believe that's what it is if you make changes online) per ticket. But, the really nice thing is that if you book your flight at $124, and that flight goes down in price to $104, and you notice it, you just have to call JB and they will give you a credit for future flights. I have over $200 in credit at the moment.