They are my new favorite airline!!! Great leg room(and I have a 6'3" DH!), nice people, comfortable seats, DirectTV, good snacks, and the flights attendants are very humorous(at least the ones on our flights have been!!)
We just had to postpone a trip, and the process was very simple...they charge a $25 fee per ticket, the rest goes into a credit account and the next time you book a flight with them, they use that. No big hassle at all.