I took the time here to a/b/c Dorado, Elysium and Nio with Led Zeppelin's Whole Lotta Love. I may as well post them here.
Here are some observations on the 3 IEMs:
Elysium—Bang on the money. Everything is perfectly balanced and the texture & timbre is off the charts. Vocals are right in the middle, crystal clear, well bodied and seductive. Guitars have crunch, bite and body with zero veil behind the bass. Bass is thumping, detailed, crunchy, impactful.
Dorado 2020-- Vocals and guitars are pushed behind the bass. It does seem like a dash of the FR is pushed completely behind the bass. Vocals are present, have great texture, despite being pushed a bit in the background. Guitars have great texture and body but lack crunch and bite-- a touch of info here and there does seem nearly totally eclipsed by the bass at times. Bass texture, timbre, impact, is off the charts good.
Nio-- This one was interesting. The Nio has more of the forwardness, detail and clarity of the Elysium, but it lacks the body, texture and natural timbre of the Dorado. Guitars have crunch and bite but they lack body and texture-- at times the sound of the Nio sounds like a 2-d image atop a 3-d surface of bass.
Conclusion-- the Elysium is the closest thing to a total package IEM for me right now and this comparison illustrated precisely why. The most remarkable thing about it is that I never find myself missing the DD on the low end when I'm listening to them. Between the Dorado and Nio it's a "choose your poison" kind of situation. For those who prefer detail and clarity over naturalness and timbre then the Nio may be the way to go.
For me, as I've indicated, it's the bass response combined with the natural timbre of the mid-range that has won the day for me here with the Dorado. When seeking an IEM that has a forward and dominant bass response I went into it knowing there'd be a sacrifice in the mids somewhere. Thus, when listening to the Dorado I take it as almost axiomatic that there will be times when I hear part of the midrange lose some of its dynamics by being pushed behind the bass a bit. Regarding the bit that seems to be completely behind the bass the bright side of this situation is that it’s not a super wide range of the FR that is missing information. As I noted in my full review of the Dorado, a slight bump to 4K on EQ should open up the most recessed area of the lower treble enough reasonably mitigate the issue and remove any sense that anything is "missing". I have been using the Dorados for the last day or so with +2db @4k EQ applied and it seems to be doing the trick rather well. FR can be EQ'd in but no amount of EQ can produce the seductive rich natural timbre of the Dorado 2020.