I just prefer colt mags....I'm an old guy and like steel.......
There are a lot of new companies that are springing up and some old ones that simply don't put in the development time they should on glock lowers.......with colt there is some semblance of a standard.....with glock not so much. I have recently had several customers come to the shop with issues steming directly from their lowers.....we were able to fix yes, but a couple involved 3D printing a replacement mag catch to mke them feed reliably. Honestly, if a n upper that will run federal 147 HST's on QC10, Angstadt, NFA, Black Creek and a few of the no name 80% lowers out there plus any colt I have ever put it on as well as the new MP5 lowers.....pretty obvious that if a new company has a lower that won't feed ball in the same upper....might be something wrong. So far, I haven't hit one I couldn't get running yet... a few were a huge pain in the ass....LOL, but we got them running.

What lower are you contemplating?