I looked at a CX4 9mm at Gander Mountain. I was thinking about getting one until I held it, it felt heavy to me. I talked to a guy at the range who had one. He liked it. Accurate out to about 100 Yds, very accurate at 75 Yds. I don't see any advantage over a pistol for short range and definitely no advantage for long range. Buy an AR15, Mini 14, Mini30, or a Marlin 336. Personally for me the only reason to buy one is just because you want it. That's how I ended up with my Benelli M4. I already had a great Remington 870 but just wanted the Benelli M4 and that is just as good a reason as any. If you want it, buy it! I own a lot of guns just for that reason.
Glock 17, 19, 26, 21SF, 30SF
Beretta PX4 Storm 9mm, PX4 .45ACP, Beretta 92FS Inox
Beretta Nano, Ruger LC9, KelTec PF9, Kimber Solo
Smith Wesson 686P with 4" barrel, CS9, CS45, 3913NL
CZ-75B, CZ-2075, Ruger Mini 30, FNAR .308, CZ 452
Benelli M4, Remington 870, Remington 1100