I received a TFB550 last week and have now had a few days to check out it's capabilities in low/mid volume settings. I have not yet gigged with it but plan to take it in the near future, so bear that it mind. It was played through an Epi 210UL. Out of the box, I was surprised by how light the amp felt, especially in light of its power rating. I appreciated the extra holes on the rack ears that allow you to mount the amp in a recessed position to protect the knobs - especially nice if you use a rack bag. The overall build quality is excellent and comparable to other amps I have tried in this price range. The chassis feels sturdy. The knobs are adequately smooth, and the center detents are nice. There was a little play in the fan switch; Dave ensured that this would not be a functional problem. The graphics are well applied and clear. Tonally, the TFB is a fairly clean-sounding amp in a good way. My 55-94 sounded nice and round, but with definition. With a Jazz Deluxe 5, I was able to dial in a nice fingerstyle growl and a smooth, articulate slap tone without harshness in the high-mids and highs. To my ears, the TFB imparts a little "kick" in the attack of each note, which I really like. At first I thought it was the compressor but realized I had it disengaged. The tone shaping features are impressive. I'm in agreeement with others here about the timbre control; it seems really useful and powerful. Turn left for a rounder tone (lows and low mids boost), turn right for more articulation and high-mid emphasis. The enhance control is similar to the that found in SWR and Eden amps, but the degree of the mid scoop is, to my ears, a little more subtle. About the para EQ, I was able to dial out a midrange "rubbery" characteristic of the tone of the J-bass without totally killing the growl. After AB'ing the "switch", to my ears, any difference in tone between the two positions is subtle. About working with Dave, he was great about answering all of my questions and keeping me updated on the status of my order. The entire transaction went smoothly. We as bass players have so many great choices in equipment, and I've really enjoyed the amps that I've used in the past from the "big" companies. But there's something I find gratifying about working with and supporting a smaller company like Thunderfunk. I'll provide a gig report after a few weeks of use, but so far I am excited about this amp.