ported is mostly for SPL use, its sloppier than sealed....sealed will give you a tighter, accurate bass.....if you're going for like hip hop bass, a 15" in a ported box will do that. if you listen to classical, or jazz or soft rock, 10" in small sealed enclosures will be good for you
It really depends on the sub and how you build the box. You can tune a ported box down to a real low frequency like 28 Hz or so (depends on sub) and keep it very clean. Keep in mind that some subs are built for SPL, some for SQ. Just depends on your listening preference. Granted when you go from a 10 to a 15 there will be a noticeable difference in accuracy, either ported or sealed.
sealed will give a flat response down to subsonic ranges. ported is about +3dB louder than sealed, at the ported frequency, but ports tend to add coloration to the sound due to harmonics, which can give undesirable results.
Ported boxes are a means to bet more SPL without buying larger amplifiers. It's really a means of getting "cheap bass" if using a sealed box isn't giving you the SPL you want. The same applies to bandpass. more SPL, but not a flat, accurate response.
I've heard a W7 in a ported box and it sounded extremly nice. The noises the car made were some of the worst rattling sounds i've ever heard in my life (even with dynomat) He had the box done by HiFi house and they only sell top of the line equipment. So if that helps to know they used a ported box then there ya go.