If you compare both laptops on their advantages, the air and live longer and better keyboard(+ touch id is) in itself in terms of ergonomics nicer.
About the same in all the tests ahead of air (not as much but still) and it's important because in the music programs need a power supply under external effects and instruments.
So the question is: what is to stop the choice if the laptop will be used for music, and for studying(a while even as a primary computer), given that I'm not important to work with graphics and video editing?