One huge difference between the green-box PMAGs and the PTS mags is that you can easily disassemble the PTS mags, whereas I haven't yet figured out a way to disassemble the green-box PMAGs. This is a real drag because if you do manage to get what would otherwise be an easy-to-fix spring/follower jam, you may be out of luck with the green-box PMAG. I've already fixed one jammed PTS mag by quickly disassembling it. Unlike some mags I've seen taken apart, it has a trap-door design at the end of the feed path for easy spring re-insertion.
Definitely something to consider.