My PS focused entirely on my experiences over there. From a plot perspective, I included a combat scene to open the statement (the other posters are absolutely correct about sanitizing what you write), and then described how my particular position as a "fiscal ambassador" of sorts for SOCCENT and how that allowed a young officer to witness events from a strategic as opposed to tactical point of view. I was over there from Dec'02 through Nov '03, so thematically I focused on how witnessing the buildup, invasion and occupation piqued my curiosity in the law.
I think being a veteran has helped, not because of any inherent "veterans preference" but because it is a rather uncommon experience among law school applicants. I believe it's really a numbers game - the only evidence I can offer to the contrary is that I wasn't rejected from any school I applied to (some obscene reaches), but then again, I haven't been let in off of any waitlists either!