AKG 701 around the house and in the car, Sennheiser HD 239 walking the dog/at work, Etymotic Er4P in bed/planes/open road to keep music in/noise out
SQ is important for me. So I always choose the E18 over using the Galaxy Note3 by itself. A reflection of my listening biases.
The E18 combo gives a step up in sound quality (clarity, transparency, dynamics) and that is important to me.
In fact I also play with High and Low Gain for each track/album to get best sound. Changing the gain setting changes absolute polarity (you have to change volume of course for each change in gain setting) and it almost always sounds better on one or the other setting (yeh crazy old audiophile - still sensitive to the muffling distortion created by wrong absolute polarity for individual recordings). By the way I don't want to get into a discussion on this forum about absolute phase/polarity, but it would possibly be interesting if you could listen for yourself, and perhaps we could compare notes by PM.