I use this at gigs and rehearsals. I need to be able to switch from an overdriven rock sound to an acoustic sound in a flick of a second and this does it.
The sound quality is good and the modelling is accurate. It does, however, have a slight hiss when you use it. This is probably because it enhances the upper frequencies. Also it doesn't like to be used with the bridge pickup (of a Les Paul), because the sound tends to get a little bit weird or even distorted. I recommend using it with two amps, or straight to the PA, because then you can switch between the electric and acoustic sounds really easily.
Rigidly build as all Boss pedals, nothing bad to say about that. Never had any problems with the pedal and I've had it for at least five years. So nothing to complain about the quality.