It has a great mellow sweet clean sound that's perfect for jazz, the reverb is usable but slightly distant sounding. It does break up a little bit with the volume on the amp and guitar on 10, but the breakup is not entirely unpleasant, not as nasal and harsh as could be expected from a solid state amp.
It can sound a little boxy when on the floor, but the boxiness disappears almost completely when tilting the amp slightly. A little more headroom would have been nice, and a slightly more responsive treble knob, as dialling in a bit more "spark" in the sound is tricky, but for playing sweet jazz or mellow blues in a more quiet setting it's perfect.
The headphone output is very hissy, but since that's not what I got the amp for it's no big deal for me. The amp itself has no noticeable noise, but the pickup noise is more noticeable when turning the reverb up, which is what you would expect.