Maya Software vs Mental Ray
 

I've always rendered in mental ray... haven't given Software much of a look. Do people favor one over the other? Is there a certain look that favors one render engine over another?

Mental ray is physically accurate,good for raytracing, caustics and such, it's difficult to master it though, maya software is used mostly by people who just started and need to get to grips with the software and sometimes for faking an effect, it's said to be quicker with rendering since it's not as accurate as mental ray.
I don't see any real advantages of using maya software over mental ray honestly....

i use both...
i have a spaceship in the challenge and its rendered in both. :)

Yeah I use both depending on what I need/want and timeframes, though I do generally use Mental Ray