If you are going to use it in something like the HK416 or M27, the gen 2 won't work, you will need the M3. Basically the gen 3 is supposed to be the combination of an EMAG and the gen 2 PMAG. All the appearances of the PMAG with a slightly slimmer profile on the floor plate and the compatibility with the European weapons such as the HK and FN bullpup.
The description also <span style="font-style: italic">says</span> the M3 are stiffer in the spine so they're less likely to get damaged if dropped when fully loaded.
I have the M2 version, and have used them in my personal/work rifles for several years now. The M2 has worked flawlessly in a Colt 6920, a S&W MP 15T, and a Bushmaster. Buy what you can find at the right price right now.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: dogman</div><div class="ubbcode-body">Dude, the M3 totally makes the M2 obsolete. As soon as the M3 was announced, all my M2 mags started failing. </div></div>
I know right!
My gen 1 PMAGS just started dissolving and USGI mags would spontaneously combust!..., holy sh!t it was scary around the powder bench...