If we could offer an alternative to Magpul PMAGS, off the top of my head, I can’t think of anything but Lancer Magazines. These seem to be extremely popular with competition shooters because the Translucent body helps them know what they have left in a magazine but in the real world, I don’t think counting bullets matters that much. There are considerable differences between something like the Magpul window 30rd AR15 magazines and the Lancer, though. Lancer magazines have steel feed lips and the PMAGS do not. This is something that was somewhat of an issue with the Gen 2 PMAGS in extreme cold in Afghanistan because the plastic feed lips, at high altitudes and sub zero temperatures were cracking. The Lancer claims their magazines hold up below ZERO and up to 150 Fahrenheit so that should prevent anyone from thinking they are “plastic” magazines.
One thing you have to consider if you are looking to add to your collection is whether or not a certain brand is going to work in your gun and the mags will drop free. There are plenty of guns out there that are setup for USGI Magazines that may have issues with other brands, Lancer Magazines, Magpul, Thermolds, but you have to think about what AR15 magazines are being used out there and is your firearm up to modern specs and should you modify your magazine release or just change brands? There is some truth to “out of spec” magazines not dropping free, but you really need to do some testing in each of your firearms to know for sure if it works for you. There are 556 and 7.62 magazines from Lancer with the clear mags. The ability to count bullets on a magazine may not mean something to you but it “may” help you to know if you got plenty left or if you need to do a tactical reload.