A clamp-on mic stand for the gutar amp is very practical for many situations. I'm using the Millennium Amp Clamp during rehershals and plan on using it live too. It's very easy to mount and there is no risk of bumping it out of position.
There are two flaws with the construction. First, the gooseneck is not flexible enough and tends to flex back when you try to position it. It's difficult to get it to point exactly where you want it to point. I'm going to replace it with a better goose neck (any mic stand goose neck should be possible to mount).
Second, I would have wanted it to be able to accept wider cabinets. My fellow guitarist in the band has an Orange 2x12 cab, and it's too wide for the amp clamp.
In summary, it's a nice product, but make sure your cabinet is narrow enough, and you need to plan on replacing the goose neck.