We flew on Spirit out of Atlantic City last summer. We chose them because of the convenience of not having to drive (and park) to Philly or Newark. I guess we chose the airport not necessarily the airline.
We got what could be expected on a low fare airline. It was no better or worse than any other. The aircraft was rather new; however, the passenger compartment was not cleaned very well prior to our flight.
The flight attendants on our flight were great. Our four-year old son was petrified of flying and they gave him such extra-special attention.