I've been using this on stage and in rehearsals as a keyboard player and in an acoustic duo, and it does its job well. At about 1m height, it feels very stable and it has so far never been knocked over.
But the one downside is that if it does get knocked over, the holder will fall apart into three pieces that take a little while to reassemble again. It will hold my tablet perfectly (and securely enough to trust it upside down), but if you're not careful with it, the holder easily falls apart.