I've switched from SW to Jet Blue and have been extremely happy with that decision.
We always flew SW and were happy with their policies, flight times, and cost. What used to give me panic attacks was the open seating. Never bothered my husband, but I would be a nervous wreck not knowing where we were going to be seated. I hated the cattle call at the gate and everyone jockeying for position and saving seats. Even with EBCI, you never knew what you would end up with.
Once JB came to our airport, I booked and never looked back. No more worries or nervousness prior to boarding.
If we need to fly SW we will. But if I had to choose between the two, it will always be JB.