I have never had any on my bike.
It is my understanding that they are made in China.
Many people have experienced problems with them.
However, was it due to bad parts or lack of knowledge on how to trouble shoot a electrical issue...
In my experience that could go either way..
My experience with Chinese motorcycle parts in general is mixed.
The quality overall has not been as good as European, US, or Japanese.
However, some of their stuff works ok and is really cheap.
Perhaps others can chime in with their experiences...