I needed a powered speaker for a stage piano. The low-end keyboard amps I've used in the past have always sounded very 'boxy' to me but I am really impressed with the MA100. There are good high ends and the bass is perfectly adequate, without the mid-range boominess that you often get from small speakers.
The XLR out is post-fade, which means that if you use that to feed the mixing desk then the keyboard player can't adjust the monitor volume without also changing the front of house mix, which is a slight annoyance.
I just wish that Thomann had used combo XLR/jack sockets for the inputs. Not all stage pianos have a balanced XLR line out, and it's a minor inconvenience to have to carry around a special jack to XLR lead.