As long as you are not doing a flight/hotel package, you will get the same benefits booking direct with the airline. Actually for airlines that don't offer 24hr cancellation, Travelocity does. If you book with Travelocity Amex you will get 6% back toward travel.
This is an idea, 6% of 5 tickets is $400 which is something. I didn't like the fare warnings on travelocity, "name changes not allowed, other changes $300."