My guess would be - it all depends on what you are trying to accomplish. Are you a competitive powerlifter? are you planning on lifting raw or equipped?
Obviously the wider stance is more suited to wearing equipment than not...and for whatever reason (I'm not quite sure how or why) box squats have earned some reputation for only being worthwhile for equipped lifters--when in actuality box squats have been around alot longer than the exotic equipment that is worn now. So if guys like Bill West and George Frenn were using them, I'd guess that their stance was somewhat narrower than what we see today.
You could always give them a shot and see how they work out for you.