I have a KD-C8 XM-L and a Palight C8 R5 also. The KD-C8 has an LOP reflector and I haven't yet tried an SMO reflector in it (I have one). My Palight R5 throws much much better than the KD-C8 from what I can tell. I have yet to find a better place to test throw. The other day I found a spot to shoot across a creek and field to a treeline at 520' (verified distance within 20'). The Palight was brightly lighting up the trees within the hotspot. The KD C8 dimly lit up the entire area. Both beat out my car's 55w headlights on high beam. Keep in mind that the R5 is also only pulling half the current of the KD C8 XM-L!
My R5 came with a bad driver which I replaced with the 1.4A 3-mode Nangj from Illumination Supply. My KD-C8 shows +/-3A at the tailcap.
Here's a link where I posted some beamshots which include the KD-C8. I didn't have the Palight at the time, but do plan on updating that post with it and also with an XM-L upgraded Maglite. Also planning an XP-G R5 upgraded Mag as well.
I have a situation for which I am looking for maximum throw (without being a pencil beam), with maximum runtime, in a fairly small form factor. I'm really liking the XP-G R5!
-Garry