The build quality is good.
The device is very sensitive to the way you put it on the head. Different angle or velocity and you'll get different readings.
It is also very sensitive to the distance from the hoop it it at, and the device doesn't feature anything to help with that. I ended up cutting a wooden block which touches the hoop and is attached to this device with velcro.
A bit McGyverish, but look what they've done with the Tama TW200, i wasn't that far =)