Both JB and SW have their pros and cons.
No one beats the fact that with a SW flight you can change your flight with no penalty. JB does not have this option.
But JB beats SW with the credits. With SW you get a credit for a fare drop, but it's ties to when you originally purchased the ticket, which can shorten the availablity. This is a reason why I love Jetblue. If the price drops and you get a credit, it is good for a year from when you get the credit....PLUS you can use it to buy a ticket for whenever. Buy the ticket before the credit expires, but the flight can be beyond the year...makes sense? On SW the flight has to occur before the credit expires...
On JB, when you get a credit, they will put entire credit into ONE account. So when I buy tickets for our family of 9, I can get the entire credit in my account (the cc holder) and I can use the credit however I want. Heck, once I bought a ticket for my grandson and his flight dropped. I called for the credit and they put it in my account even though I wasn't flying with my grandson, but it showed that I purchased the ticket! SW is going through some changes for their credits, looks like they are tightening their restrictions, so future buyers should take note of this.
For luggage SW is 2 free bags, and JB is 1 free bag. For seat assignments, I love JB. You choose your seat assignment when you make your purchase, and you can go back and change your seat assignment via online if you wish.
Then there is the unlimited snacks on JB.....and the best part, the direct TV at every seat. You need to bring your own headsets or earbuds, but you can buy them from JB for $2 -- not the best heatset you'll buy, but it works and I'm still carrying mine from trip to trip.