I used it one time for flights and won't do that again. We had decent flights to start, but then one got cancelled and we got bumped to the next day which didn't work as we had event tickets for a college bowl game the next day...eventually they got us halfway on original date and then out early the next morning to our final destination. The worst part of it was that we were now considered to have a last minute booking and had to go through extensive security screening on each flight day, even though the rebookings were their fault (originals had been purchased 5 weeks on advance).
Have also used several times for hotels with all positive experiences; Hyatt Regency San Antonio River walk for $75/night, Omni in Jacksonville for a great rate for the Daytona 500 one year and the Crowned Plaza Atlanta Airport for $48/night.
Also just had a successful car rental in San Antonio two weeks ago, $15/day for mid size SUV, ended up with a Jeep Liberty from Hertz. Was even as to use the computer kiosk to complete the rental (huge time saver).
Would not use for flights again, but absolutely for hotels and rental cars.