Another quick update: The Fiio E10 is just incredible - especially connected to the E9 amp. The E10 is nice on its own, but bests the E7/E9 combo my miles. The E10/E9 combinations is simply outstanding. So the synergy with the W4, FXT90, GRO7 and TF10 is remarkable with the E10. The synergy, however, is just fantastic and nothing short of amazing between the E10 and the FA-011 headphone.
Let's go back to the TF10. The E10 cleans the TF10 up nicely. The TF10 has more bass quantity than the W4 through the E10 (if I said opposite earlier I was wrong). Yet, the W4 maintains greater bass qulaity. Treble is little better and more extended in the TF10 than in the W4, but the Westone still maintains better mids and clearer micro details. The W4 still has the better instrument separation and wider soundstage. The mids of the TF10 (this one anyway) is not recessed, but the W4's mids are more forward in comparison. Vocals are quite better in the W4. The vocals sound a bit grainy in the TF10 in comparison. The W4 is warmer.
As I said a few posts earlier, I do hear a lot of potential in the TF10 now. I can tell an upgrade cable will really make it shine, but TF10 probably benefits from a good DAC and amplifier than any of my other IEMs. Happy listening..