Back to the topic. I've got the HD800S on my desk since two weeks. I gave it my usual 50 hours of playing without listening too much and since then I'm really becoming a fan of those headphones. I also have a HD650 since three months and a T1.1 since 1.5 years.
The HD650 was ok out of the box. With the T1.1, I heard initially a strong and puzzling metallic colouration that meanwhile completely disappeared, so either my ears or the headphones adapted (or both). I was so impressed with the T1.1 that I gave my K701 that I had used for about six years to my father-in-law, who listens to classical music only and is really happy about it.
However, I became slightly sensitive to treble recently (perhaps because my youngest daughter discovered her only weapon against the two older girls is her voice). I also found that I less and less listen to classical music with the T1.1, perhaps because trebles were too strong. I checked the LCD3, which to me was not acceptable because especially with classical music, I missed almost all the information in the higher frequencies. I then bought the HD650 that got almost all of my head time in the last months. Although it certainly has much less detail than the T1, it is just such a relaxing listening experience.
However, I now must say that at least to me, the HD800S opens up a completely new world. It offers all the detail that the T1.1 has, but without any sharpness in the treble. The bass might be somewhat less structured than with the T1.1 (which probably comes with the somewhat smoothed treble). I initially heard a certain 'plastic' colouration, probably because of the relatively flat mids. Again, either me or the headphones adapted. I now could really imagine to live with the HD800S for the years to come. The T1.1 has a much deeper soundstage than the HD650, but the HD800S indeed offers something I never heard before with a headphone: Sound in three dimensions. Imaging is just as good as with the T1.1, but I am now really sitting in the audience or even among the musicians.
Because the overall colouration is very smooth, I don't find the soundstage fatiguing at all, and I can listen for hours. Because of the soundstage and because of the detail, I can listen at really low volumes, which contributes to the relaxing listening experience (and probably to maintaining health). I am currently experiencing all my favourite recordings like I would hear them for the first time, the relatively treble-intense stuff like Oceansize or Porcupine Tree, the more dark tunes like Amplifier or Tool, and classical operas sound great. I'm not yet sure about violin tonality, perhaps I find them missing some spike in the treble compared to the T1.1.
I will therefore probably keep the other cans as well, which offers a nice gradient of treble intensity from HD650 to HD800S to T1.1. However, I feel that my mate for everyday life will be the HD800S!