Like anything else, once you get used to something being presented one way, having it presented a different way is going to throw you off a bit.
What you hear with the miles system is going to depend on your system, just like the differences in the graphics. If you're using a USB headset, you may not hear the same sounds as someone using a Soundblaster or Realtek audio chip...and vice versa.
The miles system is going to allow more flexibility with the quality and quantity of sounds within the game.
I use an onboard hi def audio chip, and the only thing that is out of whack for me is external plane engines...they sound like bees when they go by, some are higher pitched than others.