What's the difference in AR mags?

[Grub Master]

I've got some C Products with a green follower and some AR Stoner with a gray follower.
I also have some I guess they are 40 rounders that have no stamp. I assume they are mil-spec.
What's so special about Magpul?
Does one work any better than the other?
Thanks

 

[cvpadge]

****ty steel mag with a tan magpul follower is as good as it gets IMO

 

[Tech Jacket]

****ty steel mag with a tan magpul follower is as good as it gets IMO

x2 ... if those guys on Ebay want the PMags i will gladly sell them to get 3 Okay ind mags for each one.