ported will always be louder, give the same sub, amp etc. For the most part, SQ in a sealed box is going to me 10x better than in a ported box, but I've heard some ported subs that sound really tight and clean. All depends on the sub. If your looking at the Kappa Perfect (great sub by the way), I'd go sealed if your looking for some great SQL. If you listen to lots of bass heavy music (rap, techno, bass songs) a ported box is going to sound beautiful and get substantially louder.