I had one 'issued' it got as far as the arms room, I said no thanks, I was a medic, if I needed a pistol and couldn't use my M-4 (cause I'd be getting that anyways, whether or not I wanted it) I had HUGE issues and so did everyone else, bigger than just getting my pistol.
Mind you I was mounted and on the road 16hrs a day with Cav Scouts. As for pistol proficiency, medics and MP's were the in crowd shooting them.... Frankly I was scared of some of the other units that came to qualify, the MP's had the pistol trainers, they made jokes that some of us medics were better at making the holes than patching them.
Some of the tankers, literally, put my boots in grave harm, I saw a buddy get hit by a double ricochet (off a tankers boot and into his gut, left a hell of a bruise) from one of the them braking low and hitting 3 meters in front of the firing line. So in the end, I didn't mind if the XO carried my pistol, he ran the joint while the CO, um, wondered playing PL, and it was much easier to go to all the meetings with it.