You cannot sleep inside the terminal overnight, which is horrible if you miss the flight or if its oversold- beyond your control. This situation happened to me a few years ago and it was not enjoyable, hopefully it has changed.
I recently moved to the area and am impressed that daily parking is $5 per day. They are doing construction to expand the lots, hope the price will stay the same.
Recently flew United for a very early morning flight, the gate agent was awesome! She was welcoming, comical, pleasant and professional. She made my morning! Previously, I have flown US Airways into and out of CLT.. both positive, negative and neutral experiences.
Didn't really have time to check everything out, but they have some nice areas in the airport for lounging and relaxing, and also some nice eateries. Bathrooms were clean. Airport information was helpful in locating the bus stop for long term parking. The buses ran frequently and were large enough to accommodate a few families with luggage storage.