Honestly, I think they are a little gimmicky. They don't really "do" anything other than tell you that you are out of ammo....which, in theory, you should already know - but even if you didn't, I feel like a "click" is just as effective an indicator and with any other mag, you aren't fighting the recoil spring's pressure from the bolt resting on the follower as you remove it. Potaytoe, potahtoe I suppose.
What mags do you prefer?
