Works great, I particularly enjoy that the power supply is optional:
If it has power, the led indicates if A or B.
It if has no power, it still works perfectly, just without led!
Love it!
Keep in mind that this is NOT an ABY box, hence you can NOT send the signal to both A and B at the same time, it is A OR B.
I use it at the first on my sound board (before the tuner) so I can switch between two guitars with a simple foot-switch, without connecting/disconnecting any jacks!