Wow, that's pretty interesting. Same response Montell had, sort of (he just felt they were good enough to replace his IE8s, which he had iso problems with). Also, I've experimented with tips, and now feel the Sony hybrids are a good match (the OEM tips are a little bulby, and require resealing more than the sonys, which are more bullet-shaped at the end.) I also found the PFE silicones to work well with the ADDIEMs. Foamies, not so good, as they muffle the highs.
Yes, they do have a very nice detail/crispness to them, though, as Bixby noted, can sometimes offer an off kilter treble response, but not enough to ruin the positive experience. As for bass, I don't find them weak, but a good seal is critical for hearing their bass (as with most IEMs).
Anyway, they are getting some interesting feedback/reviews. I am surprised at your view relative to the IE8s, of course. Will be curious to see if you sell the Senns. Another poster, Squirsier, sold his TF10s and kept the ADDIEMs, but it was also a fit issue, not entirely SQ.