From personal experience I believe if you play on a PvE server that the Tapejara is best suited for hauling items around considering it has low boosts when you put levels in Hp or Attack. Therefore you should put most of the points if not all into Weight and Speed. It very mobile as well, since it can move forwards, backwards, and side to side. It also has a three person saddle it can be very useful in PvP. It is very fragile so be careful when you have tribe mates using the gunner seats if they accidentally hit the Tapejara and you may kill the bird. Especially be cautious with rocket launchers they will do heavy amounts of damage to the Tapejara. Also note it can be hard for your tribe mates in the gunner seats to aim if you put to many points into movement speed. I suggest pausing for a second to let them shoot then move to strafe enemy weaponry.
This Dino is my favorite on the island for various reasons. First, it can hold 2 passengers, a pilot, and carry another. Second, it is the most maneuverable flyer out there. It can fly sideways, backwards, and can land on vertical surfaces (cliffs, redwoods.) Third, it has a tek saddle, so you can have four dubs on that thing (tek saddle, 2 passengers, and one carried person.)
you don’t need to upgrade it’s stamina, if you are in the air and it’s stamina is low, just get in the back seat and wait for it’s stamina to recover, no need to land, if you don’t whistle it to follow, it will land automatically. I hope this helps :)
I play on a non-dedicated server with my family. I decided to tame a Tapejara because they have a special saddle that has 2 passenger seats. If you’re playing on a server with friends I would highly recommend getting a Tapejara. If your playing single player, I would just go for an Argentavis.