Single reflex bandpass enlcosures

whats your guys opinion on these - what advantages/disadvantages do they have over a normal ported box...even tho they are different designs just wondering your take...

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Start with this info to see if your subwoofer will work in a bandpass or ported enclosure.  Otherwise, sealed for SQ, easiest to build, most forgiving of size error.  Allows for the fullest range of frequencies.

Ported, round ports sound better than slotted, much harder to build and tune, a lot of factors in play to get it right.  Higher decibel output than sealed.  No guessing when it comes to ported, make sure the woofer parameters allow its use for vented.

Bandpass, by far the most difficult.  Never buy bandpass off the shelf.  Narrow band of frequencies, loudest SPL.  Use only when thoroughly knowledgable of how to do it.  Need other bass and mid-bass woofers to play the full range of frequencies, and well-designed crossover network. 

Found in basically two types of systems:  one, the kid on the next block who bought one pre-made, sounds like crap whether close by or far away, annoying.

And two, a well-engineered system designed and built by a SPL competitor for maximum db level.

Some good info:  http://www.carstereo.com/help2/Articles.cfm