I do prefer sealed over ported myself, overall, but my preference does depend highly upon the application.
Sealed subs depend upon room gain (pressure vessel) for low frequency extension, the type of gain that sealed rooms provide.
Ported subs create their own gain with port tuning and lend themselves well to large, open floor plan rooms.
I use a pair of sealed subs in my small open floor plan room, with extension to 16 Hz. This is not typical, but it can be done. I am thinking seriously about switching to a ported design using the same drivers, which will give me around 9 dB more output @ 20 Hz outdoors, ground plane. I could also realize more output down low by adding another pair of sealed subs, which is more of a hassle.
I am 99% music with the occasional movie. Then again, I am a bit of a bass nut. :dumbcrazy:
A friend brought his single sealed Rythmik DIY F15 to my home. My opinion is that it is a really nice sub, clean with no overhang. But four of them are needed to pressurize a medium to large size room properly.
In short, it would take four sealed subs to do the same job as two ported in an open floor plan room.