External Render for blender 3D

Hello all :smiley:

I would like to say to me, those who use or have worked in Blender, what kind of external render to use.
If you can tell me and what are the advantages and disadvantages for each one, ie a comparison of several external render.
So far in all my searches I understand how the V-Ray would be very good, but I am not sure if it’s FREE or Money
Another solution could be the girl of vray, luxrender is open-source (free) but to be able to turn an animation or a movie last very long … too hard really …
In short I would be interested if you know an external render for Blender to be free, good (animation / rendering images look real), and can export projects to 3ds Max, Maya, etc and to be used preferably production.

Thanks in advance