The reason that I chose Orbitz is because I generally find the lowest rates for Hotels through them. I have not used them for flights yet, so I cannot comment on that.
** If you find a lower rate on another site for your same prepaid hotel room, they will refund the difference and give you $50 toward your next hotel booking. You have all the way until the hotel's cancellation fees apply to try to find a lower price.
** They do not charge booking fees on hotels & flights. Plus they they dont charge change or cancel fees on hotels, because heck, plans change right?
** Orbitz is also the only one that offers a Price Assurance on both Hotels & Flights.