When it comes to rendering in Maya. what are the realities of its engine. Do we have a solid render set up or do we need other plugins to make it look really nice?

I hear a lot about V-Ray. Do we need V-Ray or can we just use Maya render by itself?

Also How does Maya act with a full scene, like a room filled up with over 35 objects that vary in size.
at what point does Maya start to slow down because of mesh overload.

Or is this not an issue here in Maya?

Last question. Can we scrub dialog here in Maya? Is there a time line for dialog regarding animation or is that something that we have to leave Maya to do?

Thanks
