We were nervous after reading the many negative reviews, but our experience was relatively painless. We had reserved an economy car but were given a Jeep, which was fine as we were mostly driving locally (like another reviewer mentioned, there were no power door locks or windows, but we didn't find this to be a big deal). The car was given to us in good condition and we weren't charged with anything extra (as far as we know so far). The service desk person wasn't overly friendly, but she got the job done.
Important thing to know: they will only let you use your debit card if you present a round-trip itinerary through the airport.