I bought this thing in order to allow an assistant to hear what I was doing while mixing. It was a bit expensive, but the size, build and features seemed to be just right, so I went with it. I wasn't disappointed - it's heavy, but that's because it's made out of some sort of bulletproof unobtainium plating. It's battery powered, and the battery housing is easily accessible (no screws). It has XLR line inputs, which is perfect, as well as TRS ins, if that works for you. The three headphone outputs have independent level control, which is perfect for when everyone is wearing different models of headphone. Most of the headphone outputs are quarter-inch TRS, but there's a parallel minijack output so that you can plug some earphones in directly without needing any adapters.
All in all, it's a solid unit, and does the job perfectly. Just don't drop it on your foot!