yeah there are advantages, first up the angel air gives very consistant output pressure meaning less drop-off, if your running an angel u can even run the gun straight from the angel air (get rid of the secondary reg) which will give even better air flow making it more consistant.
On top of the this the AIR is nice and simple to use, looks cool and WDP's servicing/tech support is easily the best out there.
Angel AIR has about the same consistency as an Armageddon. You pay a little extra for all the snazzy bits, and good looks.
It's a good system. If you can afford it, get it. I did.