Fully agree with Browning/FN factory, Euro/Indian Military Surplus and Mec-Gar magazines.
I have some of those "Asian Military Contract" w/ bright blue finish, magazines and they are OK, but I only use them as Range Mags.
About 7-8 years ago, I purchased several "European" military surplus mags and they function fine. The same for my 13 and 15 round Mec-Gar magazines.
BTW, I couldn't tell the difference from the Browning/FN factory magazines from the Euro Surplus magazines since the parkerized finish, fit, feel, black plastic followers and metal floor plates were the same... I believe that those surplus mags were in fact, made by FN.
Stay away from those "ProMags" with their "lifetime" warranty... They are not worth the postage or the wasted time, standing in line at the Post Office to send them back for replacements... since the replacements will suck just as bad... Trust me, I was one of those suckers who thought they would be fine AND I couldn't beat the price... Now, I know why they were a hell of a deal!!
Live and learn!!