If this did nothing more than consistently mix volume levels this device would be of value. However, as noted by other reviewers, it sometimes actually LOWERS volume levels and reduces tone levels. Here are my experiences:* Despite being powered by a 9v battery, it doesn't seem to work with condenser mics at all.* I tried to use it to moderate the volume (or even increase it, considering it's powered) of my passive-pickup classical guitar. While it sent the signal through and did control the volume (to an extent), it actually lowered the overall guitar volume and clarity. The guitar actually performed better when jacked straight into the amp.* Hooking up a self-powered condenser mic to this unit resulted in distortion and "clipped" sound.* Several users report hooking this up to a stereo output results in one of the channels being cut. That's inexcusably bad design. Although advertised as a mono unit-- it should still play the same sound through both channels. This one flaw alone places this unit on the Z list of equipment.So basically, all this is good for is... uh.. well, I can't think of anything it would be good for on a practical basis. Using a non-condenser mic and standard electric guitar? (dunno, I don't own one). Whatever, it is extremely limited in function and even when it does work, it tends to lower and distort the original signal.I rarely compare one product with another, but to be perfectly honest the Behringer 302 or 502 mini-mixer-- although more than double the cost-- is greatly superior to this unit and would be worth the extra money, since both models serve as preamps and have phantom power supply. Significantly more versatile than this unit-- which doesn't even perform the limited function it's supposed to perform.It's a shame. If this unit actually worked as a versatile mini-mixer, the portability would make it very useful for street performers. As its stands, I honestly don't know why they even produced the thing. I had high hopes for this device, but I'm sorry to say the low reviews on this product are accurate.Believe the negative reviews. This is a poorly-designed, badly-performing product. As with many others here-- I'm still looking for a decent, basic-function battery-powered mini-mixer. We don't need much; plug in three or four devices, individual volume controls (tone would be nice but not essential), preamp the output, provide phantom power for condenser mikes. If no one in the USA can seem to do this, anyone in CHINA listening? ;D