Originally Posted by IAHRoadWarrior
Unless there are FTers with some specific advice for us, we're probably going to go to our fallback plans - going the local travel agent route or just buying the tickets once we get to Argentina. Based on some prelim research, it looks like a walk-up Condor Class fare roundtrip is the same as the fare they want to charge us from the US (~$500), so we're starting to feel like there's not much to lose by waiting until we get to Argentina.
I would use a travel agent. We booked a package with AR Tourism in New York, where airfare from AEP on Aerolineas Argentinas, 2 nights at the Sheraton, and tours on both sides of the falls were about US $575 each.
When I tried to book the Sheraton myself, it was full, but the agent had no trouble. The tours don't add anything besides what you can see yourself on the Argentine side, and you can probably just get a taxi to the Brazil side, but it does save some hassle, and the guides are very nice.
Have a great time - we did!