Surefire's website makes it look like the 6PL is brighter than the 9PL, but has a shorter duration. I don't know much about Malkoffs...but I've seen posts where people have questions and Malkoff himself answers them....you won't get that from any other LED maker. Send him an email and ask him yourself.
The driver was designed to offer more runtime in the 3 cell configuration. However, I have found that in real use it is also slightly brighter. The difference is measurable, but in most cases is not detectable by the eye.
I have found a noticeable difference when I use 2 x Rcr123 .. I think its brighter than 2 x cr123 primaries.. the 2 Rcr123 configuration is also brighter than the 1 x 18650 ..I have not done any runtime measurements...
I would imagine 3 x Cr123 would be brighter...Im hoping to get a 9p body soon so I can have this option..:twothumbs