Another option: CDNN
I've purchased factory mags from CDNN a couple of times and the products are always as advertised, and the prices are very reasonable.
I've never dealt with Cope's, but from the responses you got it seems like a fine place to deal with.
I DO recommend you stick to factory mags, and from personal experience suggest you avoid Pro-Mag's like the plague.
IMO if you spend your money on a quality pistol you shouldn't buy lesser quality mags. for it to save a little bit of money. The proper function of the magazine is of such importance in the proper functioning of any pistol that it's (IMO) false economy to save a few bucks buying aftermarket mags..
Just my old fart opinion.
Best Wishes,
J. Pomeroy