i like both the NFBi Amp and the Violectric V281, mostly for their versatility, but also for the way they sound, but I have never really felt the need to compare them in a head-to-head shootout because they're deployed in 2 separate systems, with the V281 serving the more sophisticated main 2-channel/7.1 HT system I have, and the NFB1 amp deployed in a near-field desktop 2-channel studio-like system in my office. I am sure popular opinion on Head-fi would give the edge in performance to the V281 because of its relative prestige and price, but if I am to be honest, I wouldn't be so sure, since, as I have said, I have not A/B'd them together yet. Ironically, when it comes to the He-6, I think I have a slight preference for its performance, connected via speaker taps, on the more vintage Bryston 2b LP (which also happens to be the cheapest of the lot), because I feel the tactility of the bass a little better on it than on the other two (which is not to say the bass is anywhere near anemic, let alone, unacceptable on the NFB1 amp or the V281, or even on the Cavalli Liquid Carbon)... The other side of the coin is that the other amps, the NFB1 amp, and especially, the V281, show more versatility in driving my other cans, whereas the 2b LP handles only the He-6 and none of the other cans... Actually, I think it is in the area of this versatility with handling multiple headphones with ease and grace that the V281 may turn out to be superior to all the others. Not a single one of all my headphones has sounded "bad" on that amp. The Cavalli Liquid carbon is also good in this regard, but it is a lot less powerful, and its connectivity options are relatively limited.