I'm an odd duck... I almost always use the P4 renderer in P5. I really don't like the amount of blur in the Firefly renderer, and if there's a way for the user to control it or step it down, I haven't found it. I've used Firefly for a few images, but otherwise it's P4 renderer, shadows and anti-aliasing on, render to a new window (usually 800x800 or so.)