Sharpening a regular 20" chain in the field on the chainsaw takes literally 2 minutes, and it only takes about 5 minutes to learn how the first time. I can't see how this setup is any better than the traditional, even for occasional users. I guess many people think of sharpening chains as some sort of art that takes years to learn to do correctly, when that couldn't be farther from the truth.
And $30 for replacement chains that probably only have half the life of a regular chains at best? Boy, they really got you by the balls with that one...