I have 5 Surefire mags and love them. I normally shoot birdshot but I have shot several magnum rounds through it without a single problem. I actually plan on buying a few 8 round surefire mags. Eitherway you go, I'm sure both surefire and AGP will be good. IMO
Also I purchase all my stuff from Carolina Shooters Supply. They have really good prices, amazingly fast shipping, and great customer service.