The configuration is quick and easy to follow - it has knobs to control direct level and octave one level and then has a mode knob and another knob to control different parameters, based on the mode. It is easy to get a good sound from this and is capable of giving you a variety of different sounds. I don't have a manual for this, so I don't know how useful it is.
The sound quality of the effects on the Boss OC-3 are great as long as you stick to playing single note lines because it doesn't have good polyphonic tracking. It has a good deal of control over the octaves you can set to play above or below what you are playing, which makes for some really interesting effects. I have only used this with guitar, but is also built for use with bass guitar.
I've been using the Boss OC-3 Super Octave pedal for about three years. While this isn't part of my rig, and I only use it once and a while, it works great for what it does. It feels awesome to play a single note line with this as it sounds like a few people are playing at once! While it is definitely a cool effect, it only has so much practical use for what I do. The price isn't the cheapest Boss pedal, but if you love using an octaver, it is probably set at the right price as it is versatile and sounds great. Boss makes well built pedals that sounds great, and the OC-3 Super Octave is definitely a prime example of their expertise in guitar effect pedals.