I was in love with the ES100 for its amazing corrective (app based) eq
I used it with a short balanced 2.5mm jack cable i had made up by
@ClieOS
I operated it via my DAP's LDAC and my phones AAC
The 'lighter than a match box" / budget build quality amused me..
but...
Clipping it on clothing worked poorly (I managed to drop it into an already full toilet once... yuk) and it fell off into a puddle in a rainy street gutter too.
I now have IEMs that don't require corrective eq (Empire Ears Nemesis)
Talking / ambient while wearing them was a difficult button press
Keeping the unit close to the head (for talking) was a PITA
I am a big fan of neck band BT headphones (via my (sadly lost on a plane) Bose QC30's) they can be kept 'always there' all day (round your neck) with almost zero worry
The ES100 can't be kept 'always there - you always have to futz around with it and as said above, it's prone to fall off or accidentally get pulled and detached.