I have had this desk for more than 6 months now. It is outstanding value for money. I use it at home and for infrequent live performance. I have not tried the USB function at all, I use it as a live mixer only. It is really an 8 mono and 4 stereo channel mixer, but that is more than enough for my purposes (5 piece band, electronic drum kit, keys, bass, 2 guitars, and 3 vocals). The only thing slightly inconvenient is that the aux sends and returns are on the back - but there is so much squeezed into a small space on the main deck this is realistically the only place they could go. The signal routing on this desk is very versatile. The output is effectively noise free. The effects unit is not the most convincing - I still use an old Quadraverb for my main effects. The knobs feel good, but the sliders are a little feeble feeling. That said they have continued to work perfectly so far.
All things considered this is an outstanding piece of equipment for the price. If your budget is limited this is an excellent choice. And if your budget isn't limited it's still worth looking at - why spend more than you need to ?