I am a Beretta Fanboy, so I looked hard at the CX4, but I didn’t like it. It felt loose and the strip of plastic running from the stock to the pistol grip is, to me, is…well…weird. Also, the little extendable pic rail in front is sloppy. I know it is intended for a light, but it should be IMO, solid. The overall of 755mm (29.7244 inches) length isn’t bad for what it is. My Sub2K is a little over 30 inches open as I have a compensator on it, and 17.5 folded.
I did like the drivability of the CX4 with its ambidextrous controls, and it is a tack driver. Shoots very nice, except for the little puff of blowback you get out of the off side of the weapon. I may be the only one, but that blowback hit me in the left eye, past my glasses, every time.
With the things I found distasteful of the CX4 being stated, the Sub2K is not without its faults. The most common complaint about the Sub2K is the fact if you are shooting with the OE sights, you have to get down low on the stock to get a good sight picture. Pulling the trigger with that type of cheek weld, you are taking the recoil directly on your cheek bone every time. That chizz hurts after a few rounds.
Second most common complaint on the Sub2K is mounting an optic on the upper rail. In order to fold the weapon, the upper rail must be slick. KelTek fixed that problem on the Gen 3. There are a few flip over or twist over type mounts available, but they are bulky. The true beauty of this weapon is the folded footprint. Hanging an optics mount on one side adds to how wide the weapon is, decreasing the simple storage capability of the weapon.
On mine, I have a red dot on a QD riser mount. While stowed, I have the red dot on the lower rail. When the weapon is deployed, I have the offset sights I can utilize for immediate engagement and when I have adequate cover/concealment, I can deploy the red dot to the top rail and re-engage. Having to move the optic every time does increase the risk of losing your zero, but I have not experienced that. I can take the weapon and ping 6 inch steel at 50 yards, which is the range I would consider optimal for a 9mm in a SHTF/CQB situation. I do not foresee needing to engage targets at 100 yards or more.
I like my little KelTec probably as much as you like your CX4. There is no particular brand, type, caliber weapon EVERYONE must have. Do what feels right and practice.