I've been listening to 800S for about two weeks now. I don't know if I absolutely like these better than my sold HD 800 >:
The new cans are no longer fatiguing, sometimes I forget I have music on. That never happened to my 800. When I was listening to 800, the music always seemed apparent. I kinda like that sort of authority. Fatiguing but really made me fully aware of what I listened to. The new cans seemed way too friendly and relaxing to me. That excitement in music is sort of gone. However, if comfort is the main thing here, I guess I can live with it.
By the way, I really like the new color. At least, they stopped pretending that they are metal.
I kind of share your sentiment.
After switching to the HD800S, I no longer feel the excitement and engagement I once get from the HD800 (when driven right).
Yes, I can now listen to the HD800S for a longer period. But between the two, I still long for the fleeting excitement of the HD800. That is what that made the headphone special rather than just being normal.