Tom, I felt it was very sterile sounding. For me, I felt the tone of the Fly 5 I played sounded about the same as if I had strung up an I-beam. From one perspective, that can be a wonderful thing, kind of like the Modulus neck-thrus that I owned some years back. I suspect that for those who seek piano tones, that the Fly will produce, but it will take some help from electronics to get a tone with classic bluesy warmth. I would say that the Fly also lacked sustain, maybe the neck joint wasn't as tight as it should have been?
For comparison, I have played Zon for most of the last ten years, and those basses really provided the benefits of composite necks while still capturing some woodsy warmth.
Just my opinion, and based on playing one Fly 5 for about 15 minutes.
-Bob