Ok, I see that a lot of People seem to prefer Magpul magazines over USGI mags. Can I ask why? Also when you load you mags do you load them full or do you leave a few out. When I was places I shouldnt have been and we were locked and loaded we never loaded our mags all the way full and to this day I still dont. Would like to read any and all opinions on this subject.
I do have and use the USGI aluminum mags, and Pmags both. Between the 2, I have not much issue with either, and I feel they both work very well. Put it in perspective, I took 35 different mags with me to the last carbine course I did (Some reload all day, I just swap mags!!!

)
Pmags tend to not like round #30 until they are broken in, which constitutes loading them full, and bouncing them a couple times to be sure the ammo, follower and spring are seated. Then, leave them alone loaded for a day.
At the course, we had quite a few brand new Pmags that took full loads, but had a tendency to bounce out of the rifle unless very well seated. The broken in units were flawless.
I like good quality USGI mags. They work very well, plain and simple. Again, broken in they are better than brand new. One nice feature of Pmags is the cover; it keeps ammo free from mud and excess dirt. And, they are very, very durable.
A side note; Pmags do not 'Ping' the way a metal mag does when it makes hard contact...... they are quieter. In the right situation (Hunting) this is a pretty important thing- quiet is good.