After one small hitch it works okay now.

I bought this for my niece to go busking. It became unreliable after a few weeks. I really didn't want to have to send it back to Germany, but it was easily fixed just by dismantling it and reassembling. It has been working reliably since then (a year ago). It has a polarity switch so should be compatible with any keyboard. Housing and metal pedal seem to be solid.