Probably my favorite utility creature in the game, along with a trike. These things have high stam, weight, and respectable attack and health. Will up your taming game 10 levels by carrying many wild dinos into a good taming pen. Need to haul metal or stone from the mountains back to your base? Argy. In for the long haul, need to carry lots of supplies? Bam. Argy. My personal favorite tame, will make your life so much easier once you snag one.
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!