I see lots of harnesses that are half the price and are exactly like Aviators. Idk if they are good quality though ;-; I'll see if i can get an aviator
Aviator is standard b/c it has a lot of instructional videos etc etc...It's the one witch which most people have some experience (which can be helpful).
Do make sure you get a legit Aviator harness. For the sake of trying, I did buy a knock-off/imitation Aviator harness - it broke within a week and our boy only nibbles at it when his feathers are out of place. In contrast, our Aviator harness has been good for coming 2+ years now.