Works like a charm. No hiss or other noises. I use it in the effects loop to boost my solo's. Thought I'd need the full 20db, but a 6-9 db boost in 2-3 of the mid bands is more than enough to bust through the mix.
Other than that, the build quality is excellent, the led's are very bright and the faders are tight and won't move by accident if you kick it by accident or something. Good stuff!