trying to figure out more about RenderMan, found some old LW vs RenderMan info here >
http://forums.cgsociety.org/archive/index.php/t-349427.html
do note that LightWave these days has excellent motion blur, and you can even use some DPont tricks to cut down rendertime further.
the minus i find with RenderMan is the render quality, it's best used for NPR renders / movies as far as i can tell...
in this regard it can't compete with Kray / Vray / Octane...
correct me if i'm wrong...