I use mainly USGI in all my AR's I do have a few of those cheaps ones you can get for 10.00 at the Gun shows (Not USA Mags) they seem to work fine.

I also have one of those steel england mags. The guy threw it in when I bought my Bushy and either the follow isnt right or the spring is weak and it wont push up the bolt catch. But it could probably be fixed pretty easy.

Others here have used Thermolds and Orelites and like them.

I think its all personal preference, and what works. Not all cheap mags are going to work. And I have heard that I think it was the Thermolds wouldnt fit in some guns but I cant remember for sure.

HTH