I've had the earstudio unit for awhile because i wanted to use my audio cable for wireless listening as well as connected to the chord mojo (as opposed to getting a short Bluetooth wire with mmcx connectors). After many hours of listening (literally falling asleep with them using my shure se846s), this device is incredible despite the "limitations" of Bluetooth transmission. Not only can you customize EQ settings (i turn mine off bc if sounds better to me, but in my car i do use bass boost), but you also have very fine control over the volume as well (i use tidal streaming via iPhone X).
The clip isn't the strongest, and it could benefit from a 360 deg rotating clip, but I'm really nitpicking here. I actually think earstudio sounds better than the chord mojo--at least for the SE846s. Cleaner sound and wider soundstage to me (mojo can make them sound a tad muddy/heavy).
One thing I would definitely recommend is getting a balanced cable like one from Plussound. This makes a tremendous difference if you have discriminating ears. Noise floor is much lower, background totally black, and the quality of the music delivery is totally engrossing. I've literally refused to sleep because i wanted to continue listening, which for a wireless unit, is impressive.
Firmware upgrade was tricky to figure out on a Mac but you MUST do this to hear the benefits. I almost returned them bc i didnt wanted to bother with figuring out the firmware. Glad I didn't. Its worth every penny.