It plugs into the Rhino workspace, so you can make minor adjustments to your models and program elements on the fly. It's pretty intuitive, and packs a lot of functionality into the basic package. There's also a Pro package if you need more advanced machining strategies and other features like 4th and 5th axis support.
Unlike with other high-end CAM programs, there's no annual "maintenance" fee, and tech support is free. I use it myself, I like it, and I also sell it, at a discount, and I can bundle it with Rhino 4 for further savings. See the Toolpaths page of my site for more information about it.
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