The big question is what are you really trying to do? CAD modeling or CAD/CAM? What CAM padkage are you using with Rhino? I have Rhino and it is great but I don't have the money for the additional CAM system on top of Rhino.
You need to ask yourself some questions about what products you are going to produce. Are they truely 3D shapes with curved/rounded surfaces or more 2.5D with curved edges and only a change in depth? What you are cutting has a lot to do with what you should get. Complex 3D surfaces will definitely be easier to model in Rhino but I know nothing about RhinoCAM to generate the actual Gcode program. Curved surfaces = ball mills = lot of paths = lots of time!
Don't get stuck in the 'It is not like ACAD' or 'Not like what I am used to using' because you will shut yourself out of a large market. You are going to have enough issues and problems when you go to the CNC side to cut everything properly. CAD/CAM is not an easy artform. You learn through experience, the program does not do everything for you. Start low and perhaps upgrade later if needed.
Don't take this as a negative. You just really need to evaluate what you want to do.