I have made money with my CNC plasma table but it has mostly been a support machine used in conjunction with contracted fabricating projects. It's hard to separate exactly what to assign money to when you use several machines during a project. I can say however that if I didn't have the plasma table I could not have done several of the projects that I have completed and made money on. It's a strong spoke in the wheel of my shop.
I want to convert my mill to CNC also but have little hope of the mill making me any money. I want to just do it for the enjoyment of having it.