Not to knock the CX4 but I've seen many of them run with hiccups at matches and I've beat a bunch of them in matches with the Sub2000.

That isn't knocking the Sub2000 or bolstering, but I've seen multiple CX4s develop issues during rapid fire and at matches - some of which I always contribute to individual factor rather than weapon system but I've seen it a multiple times.

The CX4s seem to suffer the same way the 92F does from aftermarket mags as well. Every one of the ones I've shot were mag sensitive with aftermarket/extended.

It is a nice shooting platform but it isn't my top 9mm carbine. YMMV

One really nice 9mm carbine that I own and have thrown a lot of rounds through as well is the Bushmaster Carbonfiber 9mm AR Carbine. It's nice because it's the same platform as a weapon I frequently use and train on and I can mount the same optics as a rifle caliber AR. The Bushmaster Carbon 9mm with an EOTech Holosight is a fast combination.

Thing is, there are several decent 9mm Carbine platforms out there. Sub2000, Colt/Bushmaster/AR 9mm, Beretta CX4, and Marlin Camp 9.

Find the one that fits your individual needs.