Here might be a good start for you :
The Hypershade : Overview and Description
I would have thought using node based composition like in most dv software would have helped you immensely, i used digital fusion and shake before using Maya and found the transition quite easy on that front.
i tend not to use mentalray unless i want a real good look at what its gonna turn out like, bcoz of the slow rendering time.
but hey i dont know an awful lot coz i only started using the app like 3 months ago
Ohh you might also find this useful (if you havnt already)
3D Studio transition to Maya PDF
"Everybody loves a joker, But no one likes a fool"