So I had the Mojo in house for testing, and I have to agree with
@Currawong's assessment. Esther Analog keeps up very nicely with Mojo. If you're looking for a fuller sound than Mojo provides without sacrificing detail, Esther Analog might be the sound you're looking for. I really appreciate Esther and Mojo's musical sound signature that doesn't feel like it's exaggerating any part of the sound spectrum like I feel with some other DAPs that are touted as being highly dynamic, super 3D soundstage, etc. What you get with these is two different takes on what I feel is a nice warm sound that is very natural.
I felt Esther held the upper hand with my HE400 and the Edition X I just got in to play with. They sound great. Esther also plays very nicely with a lot of my IEM.
Where I feel Mojo has the upper hand is if you don't want such a full sound. I also found that the high driver count Empire Ears BA IEM had sound sig alteration with Esther that wasn't present with Mojo. With lower driver count Empire Ears IEM, I didn't have issues. I'd say the cutoff for this was 6 or 8 drivers. I noticed it mostly with Empire Ears 10 & 14 driver IEM, where I started losing upper end details with Esther. Can't say this will be a significant issue for other high driver count BA IEM, though...