I've done it a few times before but it was too much upkeep for an unappreciative girlfriend. Now I just use a trimmer on one of the low settings once a week.
Quick question. Has anyone ever used an electric razor, not trimmer, down there? Like a flathead electric razor (not one with the three circles) that you'd use on your face. I've considered it, but it's a little too intimidating. However it gets my face extremely smooth, why wouldn't it work wonders on my balls?