These in-ears are, simply put, amazing. They are, all things considered, extremely hard to fault. They are not designed with bass heads in mind, which is probably a good thing because it makes them sound wonderful all around. These new HiFiMAN creations should be on the shortlist of any serious music listener that is on the go. The new design is very well crafted, and HiFiMAN has taken a huge leap forward in terms of ergonomics and general quality. We miss a way to store and keep the earphones safe while on the move, but it is not a major issue, since the new housing and cable designs are quite durable. The hybrid cable is a stroke of genius because the part between the jack and the y-split receives a lot of wear and tear. Beefing that portion up while leaving the upper part alone gives you a durable cable that is very silent in terms of microphonics.
The midrange on these in-ears is just something else. It excels at portraying even the smallest detail and has an exceptionally balanced sound. The RE-400s are not sibilant in any way except for on horribly mastered recordings - those unfortunately exist in vast numbers. For a serious music listener, the RE-400s are just what you want. These in-ears are equally well-suited to casual listening on a train or bus, since the new design makes them more comfortable than most $100 in-ears on the market. If you can live with a bass that is slightly less bonkers than on musician endorsed headphones, these are the ones for you; they even come at a shockingly low price considering their performance.
The primary issue we have encountered with the RE-400s is the tip selection. You only get a few tips, and they are not as good as those of competing products. These are inexpensive little things and ultimately a preference thing. The good thing is that the RE-400s only cost $99, which makes a $10 shopping spree for the tips of your preference easy, and the supplied tips may just, with some luck, fit you perfectly since no two ears are alike.

HiFiMAN once again proves that they set the bar for sub $100 in-ears in terms of performance.