Pros: Easy to drive, lots of bass if you like that and very comfortable
Cons: Not very resolving for headphones at their price point.
For some years now I've been pondering a good transportable headphone rig, including a good pair of closed cans. I tried the ED9s twice and was disappointed that I didn't feel they were any improvement over the Denon D5000s I had at the time, especially with the S-Logic making the sound more as if it were in my head than other headphones. With reports that the ED8s were more neutral, I decided to give them a go.
As much as I tried to like these headphones, all I got was bass overwhelming everything else and very average resolution regardless of whether I used an iPod or high-end gear. While the sound signature might be ok for pop or the like, it was hopeless for jazz and classical. I simply couldn't listen with them for more than 5 minutes before wanting to take them off and go back to my HD-800s or, later, the LCD-2s. The only redeeming feature was that they performed reasonably even out of my iPod.
Thus, if I'd been the kind of guy to take very shiny headphones out in public, they might have made for good portable cans. However, I was constantly worried about scratching them and fingerprints. While I had high hopes that the issues with the Edition 9s had been rectified (harsh treble and boomy bass stock that requires mods to fix) and that they might make good travel cans, I was very disappointed. They are very pretty though, and would probably be good for people who want to show up their friends who own Beats with something more visually impressive. Ok, that's a rude comment, but seriously, I was that disappointed with them. I thought the ESW9s, ES10s and ESW10JPNs sounded nicer at a third of the retail price or less.
I recall comments that the HFI-780 with mods could be turned into 90% of an ED9. I think in much the same way, the price disparity of the ED8s doesn't make worth $1500. I said elsewhere, if they were a third, or half their price, I would have felt the sound quality was far more reasonable.