Worked for 12 years at a plant that made Antifreeze, both finished product and raw stock. Sold by the train car full. Guys, very little difference in brands, very little. Some of the biggest differences is dye (color of finished product). Mostly it is water and glycol, then you add more water at the customer level to raise to 50/50. I still to this day buy straight antifreeze and then mix it to 50/50 prior to pouring it in the system and I use a paint filter, faithfully while pouring it in.
Remember this stuff is made by a bunch of guys like us that work swing shift, 24/365 with 7 days straight @ 8/day and if your relief does not show for his shift, you stay another 8 hours then 2 days off. Just imagine 4:30 sunday morning and you are mixing a train car size load and it is snowing/raining and you are outside on top of the car? Imagine.