I just read this reallt cool article about some different renderers available, and how they match up.
http://www.zaon.com/company/articles/3d_rendering.php
It also has a bit of insight to various 3D apps, and how to choose which is better for you. It looks at them all fairly and with an open mind. A good read.
So what are these 'Big 6' that the guy is talking about? I can think of Max, Maya, Softimage, Lightwave and possibly Houdini, what else?