It's true that magnetic ballasts aren't capable of pushing an hps bulb as much as an electronic ballast...The difference isn't enough to outweigh the reasons why I use them. They never break, and if they do I can fix them myself. Over my grow career I've bought more than my fair share of electronic ballasts, I only got two working ones left. All my magnetic ballasts still work. And I got them for dirt cheap because "they didn't work".
Now if you're going to the growstore and I'm reccomending one...The electronic is superior. But for my needs, and my resourceful nature, I use the magnetics.
I respect your insight tho friend! You're not wrong, I just have different pros than other people lol.