hey man i have both,

so carrera low price, pretty good st of tools, very good for the price if you want to have in Cinema 4D all the tools you got in carrera you gonna cash...

however cinmea 4d is far better, much easy to learn, and very powerfull much more than carrera, the render engine is so much supperior,

cinema 4d is for big production, carrera is for amateur and up.

then cinema can be use with vue, and have a plugin interposer pro, but as i say you have to cash a lot.

so carrera is very good indeed and way cheaper than cinema 4d,
but cinema 4d is far more supperior so it's price...

but you can try cinema 4d for free, only you can't save, very good to get to know the program,
and the cinema 4d comunity is bigger too.

hum the shader in carrera seam to be more complex (node based) to be honest i haven't got the brain cell to figure them out... so i prefert cinema 4d shader, and with final render stage 2 a plug in you can have it too (but still the price...)

so if money isn't a problem go for cinema 4d with all the bell's other wise stick to carrera, it a very very desent apps.

hope that would help you...