In my opinion, the Argentavis is the Pteranodon 2.0
The Argentavis is has more Stamina than the Pteranodon, which makes him the perfect winged Dino to hunt down flying Dinos like the Quetzal. The wild Quetzal always flee from his Attacker and with the low Stamina of the Pteranodon it's nearly impossible to hunt and tranqualise the Quetzal. With the Argentavis however, this shouldn't be a Problem. Plus the Argentavis isn't only high Stamina, but also deals good Damage to his Target and is able to carry many different types of Dinos,but unfortunately like any other Dinosaur of his size only one at a time.
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!