I personally have used C4D for more than 6 years now, but I am not working with it on a professional level atm. If you don´t need to exchange 3D-Data on a regular basis, it´s not really important what software you use.
I must say that I like C4D better than 3DSMax, but I haven´t worked with a version of Max for at least 10 years now.
While C4D is quite intuitive, it lacks (or lacked? I am still using the V9.102 since I didn´t want to spend money on updates) a few functions like real NURBS modeling.
If you don´t want to do character animation I suggest you get a Modeling software like Rhino, or it´s smaller relative "MOI" (both specialized NURBS modelers), Zbrush for charactermodeling and enhancing your conventially modeled 3d objects, or even Sketchup for easy architectural visualisations. Then you can get a specialized rendering software like MentalRay, MaxwellRenderer or Luxrender, or IndigoRender , all of them IIRC specialized unbiased renderers based on physical calculation models to achieve the most realistic image results.
Concept designs and 3D illustration might include a good amount of non photorealistic rendering needs, which can be done with Cinema4D´s advanced renderer module, which I believe has been included with their current V12 release.
But before you go out and spend money on software you should take a look at Blender
www.blender.org It´s interface might be scary at first, but it can be adjusted to personal preferences. It´s a very powerful application with a huge user base.