I hate to be a Negative Nancy, but...
My first SureFire was the 6R. I hated it so much I converted it to a 9P.
I purchased the 6R for police patrol. My problem with it was twofold: 1) the batteries would not reliably hold a charge, and 2) there was no prior warning that the battery was about to die -- it just went from white light to dim to out, that fast.
Because I liked the length of the 6R, which is longer than the 6P, I decided to order the A19 adapter (6P to 9P) to replace the 6R's A14 Adapter (6P to 6R). (The 6R is slightly longer than the 9P.) Because I wanted lamp commonality between my Remington 870 shotgun WeaponLight (SureFire model 618) and my flashlight, I installed a Z20 battery spacer in my 9P so I can use P60 lamps in both. I also replaced the 6R flashlight bezel with the Z32 shock isolated bezel (in case I dropped the light I didn't want the lamp to break). Lastly I installed a Z41 waterproof lockout tail cap switch (because it rains a lot here in Washington).
I'm very happy with my "new" 9P flashlight, much a happier than I was with the 6R.