It's pretty simple for me. They are both used exclusively with my iPod. When I want glorious, smooth midrange, with slightly veiled highs and bass I can feel, I use the E888s. When I want details, details, and more details, I use the ER6s. For me, better recorded music has me listening to the Etys, while a lot of the stuff on the iPod (50s-60s rock & soul) needs some smoothing out via the E888s. Comfort-wise, I like the E888s. They fit perfectly and I forget they are there. The Etys are comfy, but I still know they're there. As with many of the things in this hobby, there is no "best"................only "different." Just my opinion, of course.