QTR-Quadtone RIP

Hello,

I have discovered QTR on the web and read many positive stories about
it for making great B/W photos. Here is my question: why buy and use
QTR if i can use the advanced B/W print option in the epson R2400
driver which give me exellent results? What are the differences
between the RIP and the epson utility? Can i expect even more better
results with the RIP?
I hope someone can help me with these questions.
thanks, Steven.