I certainly have not heard every story that has been posted, but the CF boom on the CX has proved to be a good part. Because the tail is not powered, the tail doesn't see much stress. If the heli is well balanced, the tail sees stress only in a crash.
Note that Carbon Fiber is, as the name implies, Fiber. The boom is stranded much like bamboo. Each fiber is like a carbon thread and it runs from one end of the boom to the other with all of the threads going the same direction. That makes a boom that is incredibly rigid if you try to bend it but it can be crushed fairly easily if you pinch it. That's the nature of CF. It is an engineered fiber and it only has strength in the direction that the application requires. That's why CF USED to be the material of choice for single rotor helicopters, but now we all use aluminum. The CF tube was very rigid and handled the torque of the tail rotor well, but one blade strike and it was done.
My Belt CP uses an aluminum boom. My inexpensive Falcon 40 uses a CF boom like my CX has.

The fact is, the boom on the CX makes the heli look authentic, but it serves no purpose. You can remove the canopy, the tail, skids and everything not needed to fly and with the battery placed to balance the CX it flies just fine. Over the years there have been coaxial helicopter drives built into some really weird contraptions.

I hope that gives you some ideas about how much you may want to spend on a tail boom.

Soloboss