Not trying to be disagreeable to the aluminum fans but the only thing not 100% in PMag use for me has been some lower/upper combinations are a bit harder to seat with a closed bolt. That has been it.
Aluminum mags have been near perfect as well except when they were dented in some small way but I can't fault them as that is material and wear.
I have not owned more than a couple dozen types of lower/upper combos but 100% for Pmags has to make me wonder what is wrong with an occasional AR when they don't work
My problems, few as they were, with aluminum comes from running drills which necessitate dropping mags in sand, clay, grass, cement and inadvertently stepping on them or kicking them in those drills. Aluminum are (more) easily damaged particularly on the feed areas..
I have no loyalty to any maker at least no other reason than proven (to me) results and perfect (so far) is a hard score to beat.
If I am just lucky, well, nice to be lucky at something