It is a very neat product and very useful. Keep in mind that you must have enough images in each batch to make it work at optimum efficiency. What it does is to group the photos within a batch by fstop and then it profiles each photo looking for areas that are identical in each photo that have the potential of being dust shadows. Then using this "map" it removes the dust shadow from the image. So the more photos for a given fstop in the batch, the better it works, because the better map it has. It does take a long time to process a batch, but if you just start it up on a computer that you're not using at the moment and walk away, you come back to a folder of cleaned up images. If shooting RAW, it saves out the images in the DNG format. You don't lose the original RAW photo. If you have one of the newer dSLRs that self clean, then you need to be aware that if you shoot some shots, then turn off the camera and it auto self cleans (depends on model), and then you turn the camera back on and shoot more shots, that you have essentially created a new batch because the dust has moved around on the sensor as a result of the "cleaning". So it is better to avoid any "cleaning" during a given session.
"The map is not the Territory"