NOOOOOOOOOOOOOOOOOOISY.
Like most every other Boss pedal.
I used to own one, but I never used it. It made my tone sound thin and compressed as soon as you moved a knob from the "neutral" point, not to mention all the hiss that accompanied it.
Personally, I would avoid Boss. Ive owned the ME-50 (sucked), the SD-1 (NOISY-to the point where it was un-usable), BD-1 (Also NOISY), and the GE-7 (also also VERY NOISY). The old Japanese made Boss pedals were good machines, but these new Taiwan made things are terrible, I would not recommend them to anyone.
There are much better brands out there, like Guyatone, Maxon, Visual Sound, MXR, Ibanez (9 series), Zfex, Electro-Harmonix, Budda, Fultone, ect.