If I had to pick from those two, I rather wear briefs because they give better support. Though swim short is my choice because it's the best of both worlds. Swim short is what I wear under my pants.
Boxers over briefs ... no whitey tighties for me. Not since Junior High. Today it's all about commando. My number one choice is commando and boxers only if I have too.
I seem to fall between the two....."Commando" say 90% and "Adidas boxer-briefs" if/as.... needed/required... ie ; with a suit, or for soccer/running/sport
It depends on what I'm doing. If I'm going to be outside all day in the cold with thermals on under my clothes, then bikinis. If I'm wearing jeans, briefs, shorts, boxers. It all depends on the situation, and of course when I did laundry last.