I think briefs are better looking because boxer briefs can be uncomfortable. Your question is best answered by how preferences are shaped once you wear each style for a period of time. The key here...
briefs, im 14 and theyre the most comfy, they are very supportive I agree with the young man's response above, briefs (to me) are far more comfortable and supportive (if that is your preference) as...
Boxers are easier. Briefs push on both sides of your privates and doesn't feel good, and if you get a boner in a locker room, everyone can see your penis and testicles.