Just speculating here, but I think in your case it's better to separate sharpness and smoothness, since both seem to play a role. I only have VRAY for C4D and can't say how much of an influence is created by the different main programs, but:
- First of all it looks like you're using quite a low antialiasing, because the rim braces look quite edgy. So increasing the antialiasing in some way might already bring some improvement. But beware that better antialiasing typically increases rendering time exponentially, so don't go all wonky with it!

That's how smoothness is concerned.
- As far as sharpness goes, it also looks to me that you have a texture issue because you have very sharp lines between your main colour and the white refraction/specular layers that are responsible for the glossiness effect. You could try reducing the brightness of them, changing those layers to colours nearer to the main colour and/or add some bluriness on them to have them blend better into the main colour.
- Ambient occlusion is also often a cause for a pixelated look and reducing these values might bring a better result as well, as far as sharpness goes.
- Last but not least, try experimenting with your lights, sometimes it helps massively to just add a counter light (one streaming against your main light) or move a light source a little in angle to create more of an indirect lighting instead of a frontal one.
That's the hints I can give you, but I'm far from being a pro, so I'm looking forward to what others can contribute to help you.

GPGSL : Team Owner of 'Maverick Track Performance' (MTP)