In my point of view V-Ray is the best method and powerful too. Although the Mental Ray is also good but there are a lot of settings to get a good result, other side V-Ray is less complex. We can achieve good and realistic result with less options than Mental Ray.
I think V Ray is more easy to archive good results faster.
You can combine with solidrocks plugin, to speed up the process.
The competition now is more tough for v-ray ,
many new arrivals of render engines
like Arnold, Corona and Thea.
Always the competition works for the users...
if you want to master Vray it will take much longer than Mray
and after11 years of experience and having3 certificates from Autodesk
both render systems are very powerful
Mental ray= less settings and easy to master
Vray= lots of setting and hard to master
