Hi, I started flying JetBlue in the last year and I'm hooked. I still fly United depending on the route (IAD is my local airport).
Compared to United you get TV, great snacks, more legroom, more comfortable flights, and usually friendlier flight attendants (not always though). I especially like the map. The things I miss most though are channel 9 and the magazine.
The downside is less frequent flights, so if there is a cancelation or delay, you might have a very long wait.