I owned the PM3 and loved it, had a custom cable made to drive it balanced from an Onkyo DP X1. Now while it has been a long time since owning the Oppo, I personally do not feel they sound better (subjectively speaking) in fact, for me, the gorgeous treble on the Sony, and the good to excellent bass and mids (again subjective) make the xM3 the winner for me, certainly as a portable. The fact that you can get this type of sound quality from a wireless portable with plenty of comfort, although I found the Oppo comfortable, is just amazing. In fact, it was the Oppo that made me go wireless for portable. I was tired of the cable getting snagged on everything, or having to consider the way the barrel of the headphone cable was sitting to avoid cable strain. Just so much work to deal with cables, not worth it for me in my truly portable needs scenario. Ditched all cabled portables and have never regretted it for a moment.
I actually look forward to listening to the Sony xM3 and feel that it truly does deliver fantastic sound quality, enough so that I love exploring music with it, or just forgetting and listening. It must have the bass trimmed well and properly to bring out the best, but when done right, it nails it for me. The treble is bloody brilliant, cymbal work is one great test of natural tone and having played drums for over 30 years I personally feel the treble is very cohesive and natural sounding. My take, nothing more, nothing less.
