I'm afraid this sort of thing is usually said by people who actually don't have much experience of what a live classical orchestra or chamber group sounds like. I have an HF5, not an ER4, but the sound that comes out of them when fed a good recording is exceptionally realistic to my ears and in particular is incredibly accurate at reproducing convincing instrumental timbres. What people call "dryness" is actually what real instruments in a real hall sound like. Equipment that adds "lushness" to the sound only detracts from that kind of realism. All IMHO of course; these things are a matter of taste.
My thing is, how good is it compared to iems with a good soundstage? I heard the HF3, and it sounds amazing. However, SS is not it's best quality.