I have 3 AGP ten-rounders, and have put about 500 rounds total through them (50 buckshot, 50 slugs, about 400 various birdshot), and haven't had a single problem. I have, however, knocked the feed lips off my factory 5-round mag when trying to seat it in the mag well, resulting in all five shells spilling and the ground and the feed lips hitting me in the face. After reading the post about rusting mag springs, I removed the baseplates on all my Saiga mags, cleaned the springs and sprayed them with gun oil.
In my experience, AGP mags rock!