I use these a lot..
I really like the 15 round model because the floorplate is smaller, and the last two rounds are hard to feed in the 17s. The 17 rouns model is nice, and great for the price, but your recoil spring has to be strong enough to strip that top round. I use slightly stiff Wollf springs, and have no problems.
The very best of both worlds for me was to chuck the 17 round mags, but switch the follower from my Mec-Gar mags with the steel ones from the KRD mag. I took three of them, and their springs, and loaded them into the 15 round MG mag bodies for what is, in my opinion, the perfect mag. holds 15 rounds, doesn't rattle, and locks the slide back every time.
If you get the KRD Mags from CDNN, get the nickel (chrome?) ones, as the mog bodies in the parkerized ones are a little rough, and I think they are the same price.
Steve.