IMO you can get good sound with almost any tip(for some it might require a tad of EQ still). but the sad truth is that there always is a sweet spot to find, and getting it on both ears can be a real challenge. the strength of the triple flange to me is that you go up to the second bend, put the tip of the tip neatly around there(also makes for a mad isolation at that point) and you're done.
with other tips you just don't know where to go until you test for yourself and get used to finding that sweet spot again. so it takes real practice.
I personally don't like flanges, so triple service of that .... no thank you. but I admit they are the most convenient tips if you can stand them.
I think most tips sound similar if you can get the same fit/seal, etc. However, the comply tips cut the treble response in a negative way, so I don't believe you can ever achieve the same sound with those. Not that they're bad, but not the same. Even the ety foam sounds better when fit well.
But the triple flange can be made into a double flange :)
well I use comply on every single IEM I own, except on hf5 and er4(for mc5 I go with comply, treble aren't there anyway). so I might not be in the best place to say you're wrong ^_^.
I use them a lot too, and on some iems they actually improve the sound, however with the er4s i believe they do not. I used to think there was little difference between those and the silicon tips with the right fit. Only after months of using the comply foam tips (old and new tips) and then switching to the triple flange to test again was the treble difference incredibly obvious. The comply foam cripples the instrument separation and attack dynamics a bit which makes them sound dull in comparison. I will never use them again. I always heard a difference, but it seems small. However, it's hard to do quick a/b comparisons with the er4s. So after a a long time getting used to them it was easier to tell.