I use this pedal with a lap steel guitar and with my Tele and Strat. As the lap steel has a P90 pickup, and the Fenders obviously have single coils, I can't comment on how well this pedal suits instruments equipped with humbuckers.
The pedal is true by-pass, well-built and well-finished. The case is aluminium. The battery compartment is accessible by undoing a screw with the side of a coin, which is handy if you don't have a screwdriver to hand (but obviously not as handy as a Boss-type spring loaded compartment). The pedal can also be operated with any 9V (negative centre) mains adapter.
There are four knobs - drive, level, bass and treble - whose function is self-explanatory. They all offer a good range of adjustability. It's useful to have separate treble and bass controls instead of a single tone knob. In addition, there is a two-position mini-toggle switch to adjust the pedal's bass response.
How does is it sound? Well, if, like me, you dislike heavily distorted guitars, the MojoMojo offers a good level of overdrive that is not over-the-top. I play my lap steel through a transistor bass guitar amp with a 15-inch speaker, and the pedal allows me to add an appealing raunchiness when play blues riffs in Open E. My Strat and Tele go into a Vox AC15, and this pedal adds a great lead sound to the jangly tone of the latter amp. The pedal's bass response is good, although the mini-toggle switch is fairly subtle in its effect.
In conclusion, this is a good overdrive pedal, and excellent value for money, if you want an overdriven sound rather than heavy distortion. In my view, it is ideal for playing solos on single coil guitars while preserving the basic tone of those guitars.