the simplest answer to the question is are you going for SPL(volume) or SQ (sound quality) if your after the maximum volume from a sub, that is suitable for a ported box of course, go with ported, if your after smooth response and accurate sound reproduction and are willing to give up a few decibels of volume, go with a sealed enclosure. Personally I have a 4th order folded horn bandpass for the lower frequencies, and a pair of 10's in a sealed box for the upper end of the low frequency spectrum. Best of both worlds in my book, but you lose a LOT of space.
Corey

__________________
where are we going, and why am I in this handbasket??