I picked one up to use on my live rig. Absolutely great little mixer. Never had a single problem with it. As for the pre's, they're decent and clean. I like the improvements that Behringer did with the IMP they put on the new boards. They get a little noisy when you crank the gain up too much, but that's expected on any budget mixer.
The only think that I don't like about it is there is not off/on switch. You've got to unplug it to remove power to the board. I fixed that by installing a switch in the power line to the mixer.