The oversimplified short-answer is:
If you care about 1-15hz then go sealed/IB, if you care about 15-30hz go ported/horned.
The longer answer is:
There is no such thing as the perfect box. They are all trading something for something else.
IB and Sealed is great for small spaces, or a simplistic design (or if your goal is flat-to-3hz with a zillion cones.)
I would say that if the cone count is low, ported or horned makes MUCH more sense because you won't have enough displacement to make the 1-10hz usable anyway. Or if you don't care for XLF and are fine with only ULF.
Or in Not's case where the room is barn-sized, and the subs are 15ft away and the floor is concrete and adding more LMS-18's being cost-prohibitive (and now impossible, as they aren't made anymore.)
The main downsides of ported is the 12 or 18db/oct HPF, and chuffing at high-spl and the phase issues near tuning.
The latter only being problematic if that is the box-type you are using for an MBM (at say 50hz) and only when not using multiple subwoofers in a 2-way subwoofer design. i.e. Phase issues at the end of the covered spectrum is moot (but everywhere else, it is...)
Sealed systems obviously never have chuffing + cone distortions, only just the cone distortions.
Sealed and IB tends to suffer from a lack of 15-30hz, and bottoming and overheating. The increased excursion per watt increases distortion for a given SPL. All of this can be solved by adding more of them, until you have sufficient headroom. (But that of course is costly and inefficient...)
IMO I'd take 32 sealed subs over 32 ported subs any day, because 1-10hz is extremely important to me. I don't want to be down -48db @ 2hz, I want it to be as extended as possible. To me movies and basshead music sounds boring and wrong without single digits, it just sounds "thin" (like using a speaker set to small instead of a large speaker set to full.) But that's just me, everyone has different priorities and tastes. I understand that not everyone can afford 100kW and 32 subs, of any diameter... and not-everyone wants that much regardless...
If everyone were the same, the planet would be hella-boring. (Without bad people, Batman is just an unneeded clown in a rubber suit...
I must say though... the GHorn is one of the better 15-30hz "fart cannons" available, it still occupies the # 1 spot for the loudest single 18 @ 16hz on data-bass. That's why I modeled the HzHorn after it, it's not the most musical sub between 80-300hz, but it is loud and fun where it counts (and a pair can just-fit in my space
At the end of the day, it's your money and your system, spend it or save it however you desire most. i.e. do whatever makes you happiest. Life is too short not to. We can't take any of this stuff with us when we're gone.
Better to have done a 100 years of trying and failing, than a 100 years of doing nothing!