Excellent...Let's say 4.5 stars!
I picked one of these up from Shoreline to serve: as a backup to my main preamps; or as a grab-and-go preamp for open mics; or to serve as a pre-preamp with a very low output passive pickup system. Much to my pleasant surprise, the Gigpro performs as well, OR BETTER, with my main stage guitars (one equipped with a Baggs passive iBeam and the other with a high quality, passive soundhole pickup) as any preamp I have used. Though the Gigpro offers very basic tone controls, there is enough control to shape tone nicely, and the overall sound from this preamp is excellent. As Shoreline's product description accurately says, "sound from this preamp is as good as many floor-bound preamps". True that!
* Small and light
* Ruggedly built
* A considerable amount of tone shaping capability considering the size and cost
* Adjustable Gain and Volume provides excellent overall output level control
* Invert button controls feedback very well
* Getting to the battery compartment is a little dicey
* No phantom power or DI (though it is unrealistic to expect these things in a belt-clip preamp)
Overall: Highly recommended and a good value!
Note: The treble and bass controls on this preamp are passive. Hence, 12:00 is not "flat". Instead, turning the control to the maximum means the full range of either treble or bass is available. As one turns the control down, that range is reduces (so, you lose high end range on the treble and low end on the bass). As a result, one should start with the controls turned to maximum instead of at noon and adjust from there as needed.