A great taming mount with friends! Have one person drive and another shoot tranqs, makes tranqing flying creatures like argies and quetz a breeze, but you can also use this technique to tranq just about anything. Solo, you can hook onto walls such as cliff sides and try to fire from the saddle, although the angle tends to be difficult.
Otherwise, it makes a great "pick up" mount, use it to pick up friends that may have lost their flying mount or otherwise stranded themselves far from home.
However they are quite slow, consider putting a number of points in speed and a few in weight, especially if you want to keep up with fleeing quetz. With enough weight they can become an interesting alternative to an argy.
Once tamed you can get a buddy to fly on the it with you which makes it so much easier to knock out big dinosaurs like rexes and brontos. All you have to do is fly above it and let ur tribe mate shoot darts
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.