I love my Brightstar Little Rock (original version), which is taller and smaller width/length. It works well on top of digital components, but where I REALLY like them is on bottom of digital components.
I like the little rock much better than Brightstar's Big Rocks (which I also have) under components. The Big Rock's top panel is in direct contact with sand inside, but Little Rock has some air between top plate and sand, and you can hear sand swishing around when you tilt the little rock. The direct sand contact IME can lead to some components sounding overdamped (dark and slow), which the Little Rock avoids better.