A lot of people dont consider it in comfort, but I cant stand IEM's that dont go in deep or have at least some pressure when inserted. I've found IEM's that dont go in deep often feel like they could fall out at any second, which is very annoying, IMO.
My E2c go in deep and isolate extremely well while music is playing. I've found all IEM's to offer very little isolation (about on par with closed headphones) when they are not being used playing audio.
How many people actually own more than one brand of IEM so they can comment on this? I have the ety er6i's and the ety4S's so I can say the foamies with the 4's isolate more and are more comfortable than the 6i's, but I have no idea about the shures. I used to listen with the triple flange with the 4's but, out of curiosity, I tried the foamies and never went back. But for the gym I use the triple flange with the 6i's. I tried their foamies but they are different than the 4's and seemed much worse. Does anyone here have multiple IEM's that can respond?
-foamies are the most comfortable but are not the best isolators, maybe except for the very expensive comply tips
-triflanges isolate very well, but some find them uncomfortable because they go very deep in your canal
-silicone tips fall in the middle of the two
but of course, custom is the outstanding champ of comfort, isolation and sound
I haven't tried the Westones or UE's, but I find the Etymotics with the foam tips to have a good combination of comfort and isolation -- they don't insert as deeply into the ears as they do with flanges, and they're smaller than the UE's, so there's less "Shrek Effect" ... still somewhat low profile, as they're so small and light.
I first had the Ety's and used the two-flanged tips they came with, and was very impressed with the isolation ... but the fit/seal/sound changed slightly with yawns and moving my head up and down on plane flights (and they were somewhat tricky to get out of my ears, due to deep insertion).
I then got Shures and used stock foamies all along, really liking the "low tech" effect of using the foam tips. There is still isolation -- just not as impressive as the Ety's with the flanged tips. On a five-hour plane flight a few days ago, I enjoyed good isolation with the Shures in the (noisier) back of the plane. Whether playing music or just leaving them in my ears with no music playing, the ambient roar of the airplane cabin was reduced significantly, making for a less fatiguing flight. No discomfort, aural or physical.
I've switched to stock foamies for the Etymotics, but have not used them on a plane yet (which I consider the real test). The dark Etymotic foamies seem to be a little larger than the yellow shure foamies, and depending on one's ears, might create slighly better isolation. Even if they were less isolating than the Shures with foamies (and I think they're a little more isolating), they would be very comfortable for me -- and easier to put in and take out -- with the foam tips.