I've always been really bothered by the idea that quick setup time makes up for long render times. Think about it like this- how many times do you model your entire scene to your satisfaction, map it to perfection, and then perfect your render settings without actually, y'know, rendering? I know I don't. So, you render, see 20 things you need to change, and then re-render. And re-render again, right?
At this point, any time you've gained from a relatively quick setup on one small part of the entire process (that never struck me as being too painfully difficult anyhow) has been utterly obliterated by literally hundreds of hours you could be waiting for your renderings to clear up enough to evaluate them!