They tend to be cheaper than the bigger airlines like United and American Airlines and they give you more amenities in coach and better customer service. Everyone gets a free checked bag, a snack and drink and Direct TV for free (which is priceless when you are flying with a kid).
In addition, if your Direct TV is not working you automatically get a $15 credit towards your next flight, no matter how much the ticket actually costs. In addition, if there is ever a major delay you can get an even larger credit.
JetBlue also has a great Frequent Flyer program with TrueBlue. Every seat is available with points and their points are consistently worth more than 1 cent per mile.
The problems with JetBlue have been that they aren't part of any airline alliance. This means that you can only use the points to fly on JetBlue. JetBlue also only flies domestically TrueBlue points also expired with a year of inactivity which meant that you needed to fly every year to keep your points. Not Anymore!
JetBlue has decided today that your points will never expire!
This is perfect timing for me since I no longer need to fly into New York and I wasn't sure if I was going to be able to use my built up miles.