I have two pairs. The first is the Sporting Clays model, and the second is the Magnum model. The latter is a Dimension One (?), the former is an older model before they came out with all that Dimension hoo-hah.
I would not recommend them. They don't seem to work as advertised. I am unable to pick up normal conversation during live fire. You pay a premium for these headsets (compared to other electronic muffs, like Peltors or the Dillon models), based mostly on that capability. If that capability is lacking, then it's not worth paying the premium.
Also, the N-cell batteries are not exactly common or cheap. I get around this by purchasing them from BatteryStation.com but if you're buying N-cells off the shelf, they can get pricey very quickly.
Last, even the Magnum models do not attenuate gunfire to a reasonable level (IMO) if you are indoors. I end up using plugs and the headset indoors.