When you hear boomy base it is usually because of a combination of 2 factors 1)poor quality sub 2)the sub is playing much louder than it should be compared to the mains. The people who are most likely to buy a HTIB or similar low quality sub are the ones most likely to also turn it up way to loud. (I'm not saying that everyone who has a HTIB or an inexpensive sub does this, but this is where I most often hear it).
All things being equal, a sealed sub will usually offer faster transients because it has a back wave of pressure. A ported sub is easier to get louder because of the port output. This does not mean that all sealed subs will be more musical than all ported subs. Several companies offer designs that try to give you the best of both worlds, and a well designed ported sub will always sound better than a poorly designed sealed sub. Bottom line is, don't put too much stock in sealed or ported...audition in person when you can, and when you can't take the consensus of the forum about the strengths and weaknesses of any sub you are looking at.
