I've read good about the Denon's and tried the PM3's. I found their comfort level dropped substantially for me after about an hour. I wanted the ortho sound in a lighter weight package than my old HiFiMan's. Frankly the PM3's were too warm and fuzzy for me...I wanted more detail. I have read the Denon's are supposed to have a little more clarity and detail but aren't going to be as-fast-as the PM3's, nor have as smooth of a sound as the PM3's.
I ended up going with some AKG K553 Pro Massdrop editions as the use-intention was for home anyways. Couldn't be happier! Super light weight, comfy, easy to adjust and tune!
I will say the Oppo return policy was sure nice, I tried mine for a week and returned them no questions asked to Oppo for a full refund. You might consider doing that if you want to truly know if you'll enjoy them or not. Did they sound $400 nice? To me, no. They were built nice, everything about them was really quite nice, and the drivers were solid, and for their size offered a very good sound to them. I wanted a little more punch to the bottom end...but these were able to provide a decent rumble. But they missed the speed and layering that I expect from an ortho after being spoiled by my HiFiMan HE-400's. So I think I went into it expecting more than the size and intention of the headphones were ever meant to provide.
So again, I ended up returning them. This was in May or June 2015, when the PM3's and Denon 400's were both fairly new. Back then there wasn't enough about the Denon's, they were the same price and their availability was crap. The AKG's kept coming up and it was a very well invested $120.
