I was worried these would be quite weak, especially the low end, but it was not an issue at all. Although not being as piercing as a glockenspiel they had no problem being heard in an orchestral setting, at least if shacked rather than pressed. It is nice to have this large chromatic range but I did occasionally miss not having two full octaves.
As for the build quality nothing has broken yet and they have sustained a few drops to the ground.