Ken,
I don't think either the sealed or ported designs are inherently better than the other. One can make a great sub or a crappy one, using either designs. However, my take is, for a given set of specs for bass frequency extension and maximum low-distortion SPL, the sealed designs tend to cost more. In other words, if I were hunting for an under-$1K sub, I would be looking mostly at the ported designs (simply, there seems to be no great sealed subs in this price range). But if I were to buy a $3K sub, I would seriously look at the sealed subs, too.
