In my case I usually hate silicon tips for lack of comfort thus I was using Westone foam tips for long time, but very recently re-tested the original silicone bi-flange hearing many opinions that these would give best sound quality.
Quite unexpectedly I am perfectly happy with these for the sound as well as comfort. Lucky one here.
Shures, Sennheisers, Westones, whatsoever,,, they include so so many variety of tips but in my experience most of them are useless to make me end up picking up what I already have... so little skeptical to think that can be a good idea for Earsonics to include as many ear tips as other companies are doing (that may also contribute to make price tag higher). However they should have at least included S/M/L sizes, if, as pointed out, the ear tips selection matters so much to the sound impression.
For the sound impression, my view is that IEMs like S-EM6 require additional time for "brain burn in" for their typical fully closed IEM design, meaning that is very different from what, for example, any open cannes like HD800 can provide.
"Brain burn in" in other expression is "get used to it" and that is nothing special.
The case S-EM6 is the very typical one but for the other IEMs there is always same argument of "sound is not right".
Roxanne Universal, W50, UM pro50... interestingly, for those (similar, in a way they all have super-multi BA drivers design) I ve also seen comments like sound being dark, muffled, congested, etc, but my guess is that after weeks of usage the impression may change drastically towards positive side for anyone.
Looking forward to testing Roxanne Universal to see how those compare to S-EM6.
("We don't need so many drivers!" argument is welcome but I also welcome diversity and love Klipsch X10 with single driver too )