I have the Behringer - I think it works fine. I'm not quite sure what you need to know, but this is how I set mine up.
I take the stereo headphone send from my Mackie (using a Y) to the left/right in on the Behringer. I then take the main stereo out from the Behringer to my monitor amp to route the signal to my near field monitors.
Under normal operation I simply send the same stereo signal to all headphone sends (by the way, each headphone channel has a button to mono the signal - a cool option).
If for some reason I need custom sends to each headphone (the drummer wants bass only, the guitar player doesn't want the much of the drums, etc.) I simply use the aux effects sends from the Mackie into the aux input on the Behringer, which allows me to increase or decrease each channel on the board (in the aux sends) accordingly.
