It's funny - I bought a couple of dozen ProMags for the Mini14 back in 2009-2010 and have had nothing but excellent service from them. I even bought replacement Ruger followers to install in them, based on the conventional wisdom of the time being that the Ruger followers were mo' better, but I've never felt the need to make the swap.
While my experience with ProMags in anything else has been poor, I'm happy with the Mini14 ProMags.