I'd seen something like this and wanted one, then saw this new Gravity model and jumped at it. I'm glad I did, it's much neater than placing a tripod-based stand in front of an amp and more compact on small stages. Nothing to trip over! And it won't tip or get kicked over, plus the position you set is where it stays for the whole gig. It can mount from the top or side of the amp, even underneath. The bright green trim isn't to my taste but you don't notice it from off-stage. It folds up to a compact size for transport or storage. Uses strong metal for most of it and the machining is accurate. It can take a couple of tries to get the exact position you want and you can adjust the position of the mic on the arm, but not the length the arm extends from the clamp. There is some play in the mechanism but in use the spring tension prevents rattling. Some of the parts are plastic where you might feel they could be metal, but it helps keep the price very reasonable. After some use I find that some mics make it sag, even an SM57. I feel it should be able to support such a common microphone without difficulty. Even a lighter e906 makes it tip slightly. It won't fall off, but it's not 100% stable. It's also easy to lose one of the knobs and the small parts that help grip the edge of an amp.
The stability is better if you mount it to the top of the amp but not all amps will suit this as it may block the controls.
