Boris lent me a Tantra for a few sessions I was doing, and I couldn't give it back when I was done - I had to make it a part of my bass arsenal. This amp is immediately so rich and warm, it is hands down the most musical bass amp I've ever played. Every note in every range was balanced, when I used it live I sat in the mix better than I ever have before (which inevitably changed the way I played). I even used it at a quiet jazz gig at a venue that normally gives me problems (I usually walk out of there with super wacky EQ settings), but this amp required very little tweaking, and it was so easy to hear even at a very low volume. TL, DR: It sounds great with minimal fussing, but what made me feel confident about the purchase is its versatility and capacity for tone-shaping (3-band parametric plus a whole bunch of other options), the compressor (holy crap the compressor), the control over the drive circuit (pent + triode modes, individual gain + OD mix knobs, option for hi-pass drive, footswitchable), and the harmonic blend (subtle blend of 2nd and 4th harmonic to help support low frequencies). In addition to treble and bass shelving, there is a full 3-band parametric EQ (+/- 5db: 34 - 300hz, 150 - 1300hz, 690 - 6000hz). This was so nice to have on stage, I loved being able to dial in exactly what I needed with so much precision (and it takes up far less real estate than a graphic EQ). There are also switches with two options for bass boost and treble boost. There is a switchable hi-pass filter at 28hz, 60hz, or 40hz to help tighten things up by removing much of the really really low frequency information. The compressor is fantastic. When I picked up the Tantra, Boris told me that this compressor was Grammy-winning producer Greg Wells' favourite compressor, and I understand why. I haven't found a reason to turn it off. Although it is just one knob, it was designed (by a bass player I believe?) to be optimized for bass. The manual says the ratio is 3.5:4, fixed threshold. There was no pumping, and even at high settings it didn't overload the signal. The overdrive circuit features both pentode and triode tube modes. There are two overdrive stages, independent gain control, and an overdrive mix knob, and a hi-pass switch to have overdrive affect only upper frequencies to keep your lows tight and present. Any footswitch can engage the OD circuit. The harmonic blend knobs are a really cool thing, I honestly didn't think I would be into it. These are activated only when the compressor is engaged, and add either the 2nd harmonic or 4th harmonic above the fundamentals (knobs labeled H2 and H4). I've used this amp mostly with a Sadowsky MV5PJ, and this feature made my low B so tight and crisp - it avoided any of the flubbiness that I was disappointed to hear with other amps. The harmonics are very subtle, we're not talking POG-level octaves - just enough to help support anything E and lower. The plethora of features aside, I'm just excited about how great this amp sounds. I used it for pop, rock, and jazz; live, and in the studio and it was awesome for all of these things. I wasn't planning on buying an amp but... you know. It sure made its case. There is an option to buy as a preamp for studio use, I bought the version with a 1000W power amp. There is also an option for 2500W(!) monster jam. I'd encourage anyone to try this thing out!