Ok, so I burned my e-Q5 in for about 20 hours now and I am not hearing much change. My biggest issue with their sound is weak separation and poor portrayal of space. I compared the e-Q5 directly with my old UE Super.fi 3s which for those who may not know are now $50 single armature IEMs. The e-Q5s have better texture across the spectrum and better treble and bass extension, but the Super.fi 3 edges out the e-Q5 in speed, clarity and actually I feel that Super.fi 3 has slightly better separation and similar imaging. And it is not even a high quality single BA design - an Etymotic ER4 will blow away the e-Q5 in separation. Now, it's not that the mediocre separation alone is a deal breaker for me, but it becomes one when combined with poor representation of space. I find that e-Q5 is much like my old Super.fi 3 in this regard - there simply isn't much depth to the sound in these IEMs and imaging is very weak so I never really feel any sense of strong presence when listening to music with these, at least not in a realistic way. Timbre is good on the e-Q5, but it doesn't help it much - it just plain lacks articulation IMO, compared to a good 2+ armature IEM or a high quality dynamic headphone/IEM like RE0, RE252, FA-003, SRH840, etc.
Oddly, from memory, I think the e-Q7 has better portrayal of space that the e-Q5 - everything sounds deeper and more dynamic through the e-Q7, whereas the e-Q5 sounds shallower and I dare say, more simplistic. The e-Q5 is more refined that e-Q7, is slightly more focused in imaging, and does have better extension high and low, but IMO the e-Q7 is still a higher end IEM because it is still very close to the e-Q5 in all these aspects, but to my ears significantly outperforms it when it comes to overall musical presentation - e-Q7 sounds more powerful, engaging, immersive that the e-Q5 and I don't care if the e-Q5 is more neutral sounding, because IMO neutrality does not equal to good sound quality because good sound is supposed to be either natural or analytical and natural sound is never flat, while good analytical sound is not supposed to be lacking technicalities. e-Q7 may have more boost in the bass and mids, but that is a part of what makes it sound natural and realistic. e-Q5 doesn't have that emphasis and then it also doesn't have the depth and dynamics of the e-Q7 and thus ultimately comes across as sounding quite boring and soulless to these ears. When listening to the e-Q5 I feel as though the music just passes by me and I am unable to engage in it and attach myself emotionally to it in any meaningful way. I felt a similar way when listening to the RE252 BTW. However, while RE252 is also quite flat sounding IMO, it blows away the e-Q5 in technicalities and that is what makes it great in its own right and a better IEM than the e-Q5. RE252 has much better separation, better speed (very impressive for a dynamic driver IEM!), better timbre and although still not great compared to the e-Q7 - a better sense of depth to the sound as well. This technical excellence is what pulls me in with the RE252 - what I may be listening to is not music as such, but technical qualities, but that is still better than not listening to anything at all. With the e-Q5 there is nothing that can really engage me.
So what can I say? I know plenty of people here love their e-Q5s and there is nothing wrong with that. Everybody has different tastes. But IMO, technically speaking, e-Q5 is just not a very good IEM. It just lacks the technicalities of a high end headphone/IEM. Especially in separation which is really still on the level of an average, inexpensive single balanced armature based IEM or a cheap dynamic. Personally, I find this completely unacceptable when also coupled with average clarity (most BAs sound clearer), not-so-great speed (RE252 and most BAs sound faster), lesser depth to the sound and seemingly compressed dynamic range compared to the e-Q7, flat frequency response and finally, questionable design choice with the very thin and fragile looking, and also microphonic cable. e-Q5 is neither analytical because it doesn't have the technicalities, nor fun because it has an overly flat response and also doesn't wow you with dynamics and musical depth like the e-Q7 did so well. Of course maybe I am not getting a perfect fit and maybe they need even more burn in, but so far I think of the e-Q5 as a failed attempt to make something original. Ok, the e-Q5 may be unique in how it sounds, but I care much more about sound quality than some unique, special voicing.
Just my 2 cents of course.