In the context of personal taste, I felt that the B2s put a little too much emphasis on treble detailing, as I often found myself marveling at the many details that constitute songs, whilst missing the overall beauty of the songs themselves. In this light I found them to be rather cold, clinical, and soulless. In contrast, I found the FXT90s fun, energetic and exciting, whilst at the same time maintaining an excellent level of detailing throughout the frequency spectrum.
I noticed sibilant sound are controlled better on JVCs, but B2s are not that cold, soulless, I compared with my Etys MC5, the latter feels more boring.
They are of course very different signatures, with the B2s / DBAs falling clearly into the analytical category. The FXT90s however are far less easy to categorize. They are mid centric, but extended well at both ends. They're very forward sounding, but not aggressive. They're fairly smooth, yet in no way laid back. Perhaps the most remarkable thing about them is the way in which they create an unprecedented (in my limited experience) balance between fun / coloration and technical proficiency. The best of both worlds in my opinion.