After using many different mags and combos, my preferred magazines are McCormick PowerMags with rounded MetalForm followers. The lower priced McCormicks are called Shooting Stars and they have a bit more spotty history than the PowerMags. I've had generally good results with the Shooting Stars but I wouldn't personally recommend them myself. I see no reason to save a few dollars per magazine when you can get fine mags for just a bit more.
I'm pretty sure the Springfield mags are still made by MetalForm. Generally good and pretty cheap. The thing to keep in mind when you get into 1911s and have several mags to utilize is to number them and keep track of which mags are very consistantly good feeding and those that might more hit and miss. Again, no reason to compromise reliability just to save a couple bucks by having a junk magazine mixed in with your good ones.
I don't care for MecGar 1911 mags.