Bought four of these now for my "G&P" SR-25, and I have to say they feel and look great for this rifle! They make an already beautiful-looking rifle look even better. The mags themself are made out of Magpull's durable polymer, so you don't have to worry about breakage. Plus the dust cover is a nice extra! As far as feeding, they feed fine in my "G&P" very well. However my gun is only G&P in externals only, internals all custom. Anyways, the mags fit very snug, almost too tight when you first get them, but once broken in, they are great.
-Magpull brand and quality
-Fits in the gun well
-Dust cover is very useful (ESPECIALLY in the Colorado Snow!)
-Actually in stock compared to the stock G&P mags
I'd say the only real con is the price, however that is the price you pay for not buying an M4. But with Magpull you do get what you pay for :D