I think a good rule with ANY travel website (travelaxe, expedia, orbitz, etc.) would be to perhaps check them first, get the lowest price you can find, then doublecheck that against the direct website (air, car, hotel) and see how it compares. If it's the same, better, worst case maybe just a little more, you might consider booking directly instead. Unlike the travel site/agency is offering some special discounted rate, I think it's usually better to book direct than through a 3rd party, especially when any changes or cancellations are involved.

Jeff