Autocad uses the mental ray engine, actually, which 3dsMax also uses. From what I can tell, as far as the digital art worl is concerned... mental ray is the red headed stepchild. It's a bit dated and seems to have inherent flaws. I can't expand on that much... however people can tell right off the bat that I use a program that has Mental Ray because, as they say, by the blurriness, color, and the way it handles light bouncing...
however, 3dsmax also uses a few others.. povray or vray or something like that (I forget) as well as it's scanline renderer, whatever that is...
Because you're already an Autodesk user, one cool thing is... 3dsmax will inherit layers from the .dwg file you bring in, and thus material assignment can be greatly hastened.
Now, Rhino with the Flamingo (rendering) addon will do the same... it has good DWG support.. but it's renderer is not as flexible as 3dsmax, as well as 3dsmax having a great deal more support for additional addons, scripting... and the shear size of the knowledge base around 3dsmax is astounding and goes back over a decade.
3dsmax can do all your basic animation as well, including animating actual objects rather than simple fly-bys... though as expected it'd handle fly-bys quite well.
Of the few I messed with, 3dsmax seemed like the easiest to get up-n-running from existing models and was not too bad to learn from, using the interwebs. Of course if you wanted to get some training, obviously that's easy enough to get some formal training for the product.