I had these phones in house for 5 days and I have to say, I was very impressed by them. Impressed enough to immediately order a pair. This coming from someone who stopped looking for headphones after getting HD800's. Two things to note beyond the fantastic sound quality. They feel heavy and uncomfortable when you first use them. Compared to the HD800's these are definitely heavier and chunkier. This really concerned me at first, but after a few days I got used to them, and was able to enjoy extended listening sessions without discomfort. The second thing is these seem to be amp/gear dependent. I first tried them with my Grant Fidelity 300B integrated. They were fine, but the high end seemed very rolled off, and the bass was loose. The only other single ended amp I had on hand was a CKIII. Much to my surprise the phones sounded much better on this amp. After a few cable swaps I started to hear what these phones are really capable off. The high end is very natural with maybe just a touch of roll off, and the bass was strong and deep. Instruments sounded right, and had great texture. Soundstaging felt smaller then the HD800's, but very realistic and accurate. Overall they are a pleasure to listen to and definitely give the HD800's a run for their money. Only time will tell which one will take the top seat in my house.