By your own omission you proved the point. HK mags are nearly 4 times the cost of Pmags. You still haven't addressed the weight difference or the fact that HK's are not available in Canada.
TDC
ETA: You can never have enough spare mags. Buy as many as you can afford and keep buying. A minimum qty IMO is 25 mags per gun.
I can afford both so cost is not an issue for me?
But if I'm going to buy a superior magazine then, i will need a superior rifle, which i own. So H&K 30rds are good for me, because i like the steel mags, and there design is very ###y, it is a beautiful magazine.
I never get feeding issues with them, i have with some Pmags, not that it makes a big difference, usually i would have cleaned my rifle 10 times before a pmag would have issues, not to mention other issues can arise as well in the gun it's self.
Mind this is if I'm running a lower end AR like what you probably run!
But I run superior high end rifle always, so it need a superior magazine, hence the need for H&K SA/80 or Emag that will shine with an H&K/416-Mr223 variant.
Plus i find the H&K 30rds smoothness to drop faster then a pmag.
I have run both, so that is my opinion.
I have only held an emag...so the verdict is still out on that...