I've used them in the past and while I did get a good deal - the flight times were awful. I also screwed up with my dates and requested the wrong departure date. Once you submit your offer, it's a done deal if the offer is accepted. I tried changing my flight through both, the airline and priceline and neither would change the reservation. Just be really careful to double check your data before submitting it. We didn't use our 3 tickets - it was about a $500 lesson that I've never made again. I'd rather pay more for our travel arrangements and have flexibility to adjust as needed.