G36 mags = big, bulky, get caught on everything, expensive
Armalite mags = fit twice as many in the same space, smooth sides so they don't get snagged or caught on anything, FAR cheaper and a lot more common, allows you to swap mags with teammates using the ever popular armalite series
I switched to armalite mags because when you have the option G36 mags don't have any advantage other than the cool factor of fake round. Tactically and financially armalite mags make much more sense assuming you don't mind the loss of aesthetics. I've died more than once because when trying to pull out a G36 mag it got caught on something (pouch flap, tall grass, twigs, webbing, etc.) and while struggling trying to get it free to get it in my gun I was hit.