Interesting, even with Yaxi pads I could not get the Porta Pros to my liking. Compared to the average IEM I thought the IEMs sounded much cleaner and more technically accurate. Stepping up to something like Letshuoer S12s absolutely blew them out of the water (more expensive, I know). Maybe I just falsely attributed that to an inherent advantage of sealing off the ear canals. Will give the Porta Pros another try.

Porta pros specifically seem to be a subjective thing, many describe them as a bit muddy, while some like that as an easy listing mode. The KSC 75 though really impressed me, for me they replaced the ath-m50x. Less base (partly because of no clamping pressure, I read, so changeable with a headband). I do have a cheap chinese hifi IEM I do like and would understand if someone preferred that one to the kSC 75, to further complicate things, but I stuck to them.

Also read positive things about the moondrop old fashioned, to mention an alternative to the porta pro in a very close form factor, not the strange ear clips that are the KSC 75.

I'd argue that the additional space should give the form factor an advantage, though sure, being closer to the ear might also be one. And no doubt, given the huge popularity of IEMs the technology must have seen a lot of progress, so I might be wrong.