Just a head's up: when Expedia books a reservation on your behalf, and they do not assign seat numbers, you will likely be bumped from the flight. This, of course, causes significant problems if you need to get somewhere. The tactic is to tell you the airline will assign seats later, but beware that this may not happen (information they will obscure in the confirmation), which will put you first in line to be stranded at the airport. If you call Expedia's customer service, you will be talking to someone in the Philippines who has no authority or ability to take any action except to apologize politely. You are on your own at the airport and they will take no ownership of resolving the issue...it is between you and the airlines. My advice: don't book through Expedia, book directly with the airlines so you don't become a 3rd class citizen.
Pros: IT APPEARS TO BE CONVENIENT
Cons: YOU DON'T GET ANYTHING FOR YOUR MONEY