I have been using SureFire C123's in my Fenix P1D CE and they have performed well. I just purchased some of the Battery Station Batteries, I got the 32pk with case.
i've used Duracells, Energizer Lithium Photos and SF own SF123 and for primaries SF123s have more bite, last longer than the rest. I now use AW batteries for 'Guilt Free Lumens'