Very good isolation, better than my Edition 8, but heavier and less comfortable. No noticeable battery drain on either my iPad Pro or iPhone 6 Plus. I purchased the EL-8 for travel, but I'm not using them on the go, just for on the plane and when I get there - if I decide to keep them. Still deciding between these and my Edition 8, which I purchased for travel use a couple of years ago. There's no need for both, and I have my HD650s for home use which neither of these phones can compare to.
The EL-8 and Edition 8 each have their own strengths and weaknesses. Listening on my iOS devices, with some recordings (I listen mostly to classical) the EL-8 is more engaging and full-bodied with better base extension while the Edition 8 sounds thin and anemic in comparison. On other recordings the Edition 8 sounds more dynamic and fun while the EL-8 sounds flat and less involving. It's really odd and quite surprising considering the EL-8 has the advantage of the on-board DAC and AMP that is supposedly superior. Otherwise why bother? Overall, though, the EL-8 is more revealing with greater detail and superior imaging, though soundstage is wider on the Edition 8.
Run through my desktop system (DAC and headphone AMP) and swapping out the lightning cable DAC/AMP for the included 3.5mm cable on the EL-8, my Edition 8 wins hands down. They are truly scalable and have a far richer, more dynamic and involving sound signature than the EL-8. But the balance tips back in favor of the EL-8 on my iOS devices, and as I already stated, I purchased these headphones for travel use. It's a tough call.