I got a set of Soundmagic E90C today and I’m pretty impressed.

Currently £89 on Amazon UK they come with:
1 x standard 3.5mm cable
1 x balanced 2.5mm cable
1 x PC audio/mic adapter
3 x pairs of foam tips
3 x pairs of silicone tips
1 x pair weird silicone tips
1 x zip fastening case

When I first tried them I was taken aback at the piercing treble and lack of bass but once I got a pair of tips on them that fitted me their sound changed dramatically.

I first tried them using an FX-Audio X6 DAC and found them to be one of the best sounding iem’s I have. To my ears the bass is powerful but not boomy and slams hard. Mids are upfront, vocals seem louder than with my other iem’s. Treble boarders on being shouty with a hint of sibilance but to me combines with the hard hitting bass & strong mids to produce an exciting sound. The sound is very clear and lots of detail comes through. Stereo separation is excellent. The soundstage is more intimate than wide and isolation and positioning of individual instruments easy to hear.
Using the balanced cable with a Fiio BTR3K over LDAC impressed me even more.

I wouldn’t say that the E90C’s have a smooth sound, far from it - to me they’re grity and raunchy and exciting, Freddy Mecury & Montserrat Caballé’s rendition of ‘How can I go on’ is to die for. They are very easy to drive but I dislike that they’re so fussy with tips - use slightly the wrong size or move the iem out of the ideal position in your ear and the sound collapses. Another thing I disliked was their use of proprietary connectors - similar to MMCX but different (why?).

I haven’t seen a review of these yet - the above is just my opinion, I’m not a reviewer. Hopefully someone with more educated ears will take a listen and let us know if the Soundmagic E90C’s are suitable for the masses or that my ears need decoking.