I'll start with a positive - this unit gives surprisingly good sound quality when playing music via Bluetooth/aux input. If this is all you want to use it for, then I would recommend this product as it does this job well!
However it's downhill from there I'm afraid. I bought this to plug in an acoustic guitar and microphone for small outdoor performances where mains power is not available. Initially I was reasonably impressed despite not being very loud - if you turn the inputs up too high, sound quality becomes poor and it can't handle any very low frequencies - if you use an acoustic guitar for percussive purposes for example, the sound will simply cut out temporarily if there's any low end frequencies present. However, it was better than nothing and did give enough amplification for very small outdoor events. (NB - I'm using a high end Gibson acoustic guitar with a great Fishman preamp and a Shure SM58beta mic, so it's not the source material causing the problem!)
After 6 months or so (and not with heavy use either, maybe once a month) I noticed that the battery was starting to run down more quickly. By a year in, I was getting maybe 2 hours out of it at best and now after 2 years I wouldn't trust it to last beyond half an hour. NB - it uses less battery power for music via Bluetooth/aux so is still pretty useful for this purpose, and this is all I use it for now.
The main problem I have now though is the awful crackling noise on the potentiometers (volume nobs!). It's almost impossible to adjust the volume on the various channels now without the sound cutting in and out constantly and an awful crackling sound when you try to adjust them. Usually this is down to dust, but I've taken them apart and cleaned them, and the problem persists - so it's probably down to poor quality components in the circuitry. I contacted Behringer, as this started happening just outside the year warranty (only a couple of weeks outside) and they completely dismissed me. Very poor customer service. I also asked them about the battery life and they said this wasn't something that would be covered by warranty anyway. I'd expect the battery to degrade a little, but to run down so quickly with relatively little use was very disappointing.
Conclusion - pretty good for simple music playback via aux/bluetooth although expect the components to fail and the battery to degrade quickly. It's not super-cheap either so if this is what you want a portable speaker for, look elsewhere and go for a batter quality brand. If you're looking to amplify instruments/vocals, avoid this speaker.