To complexity of the scene is just one thing to affect the render time. Another one, probably the most important, is the size. Ussually I'd make smaller images just to show as a jpg, but these were for printing, and needed to be very large. Also, I've used the most time consuming method, since the others, ironically, would crash 3dsMAX at some point of calcuations (with lots of RAM unused). This was also due to the size.
You may want to look here: http://chaosgroup.com and search for Vray for C4D (released some time ago), and test it yourself![Wink ;) ;)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
You may want to look here: http://chaosgroup.com and search for Vray for C4D (released some time ago), and test it yourself