Some really early impression.
Non sound impression:
The unboxing experience is outstanding, most sustainable package I ever seen.
Really thin cable and no heat-shrink ear guides, if you own the E3000, it’s thinner than than. But the material been used is definitely on the other levels.
Fits is like ER4 with additional support on the ear canal, but personally I much prefer the ER4 type of fit, mostly due to the unergonomic design of the cable.
Build and design of the IEMs is simply outstanding, look fairy futuristic.
Sound
Typical Ety house sound, if you like the ER4XR, then Yes!! it’s definitely a upgrade.
Better sub bass extension and texture, more detail in the midrange with clearer presentation, the treble also extend further and sound relatively brighter. The imaging has also been improved significantly, soundstage is also wider and tad deeper.
Sitting at $500USD price category, emmm, I wouldn’t necessary pick it over the ER4 (I can get it for $300USD now).
But, if you simply enjoy the Etymotic sound signature and you looking for more bass presence and better technical performance, then YES!! it is a really solid IEMs to get.