One of the most useful tames in Ark, especially for mid level players. I put a lot of points into health to help me carry creatures to a taming pen and a lot in stamina to make them killing machines. They can easily kill wyverns as long as the rider doesn't die. They are great pack animals, especially with the reduced weight for stone, metal, obsidian, and crystal. The only real downside is that they're somewhat slow, although they tend to have decent stamina which makes up for it a bit.
Getting a massive TLC update in March 2018. The saddle will act as a mobile smithy, Argentavis will be able to carry with Talons as well as with its beak, reduced carry weight on obsidian and a few other unannounced resources (similar to the mammoth and wood), and will also gain a Rapid HP Regen upon eating (likely from devouring corpses and not specifically food from inventory). Like so people can see!