I have 8 of the 24-round factory Glock 9mm magazines. I carry them on my duty belt. 5 are training magazines I have well over two thousand rounds (115 and 147) through my 34.5, 19.5 and 45 using these magazines. I always load them to 23 rounds. I have never had any malfunctions.
I am hoping these get more popular so at @Tony Mayer adds a AIWB-SPMP fit for this magazine.