Yacon syrup is being talked about a lot as a super-food that can help with digestion and weight loss. I think it can be a good alternative for other less healthy sweeteners. But it's still a sugar, and I doubt that sugar in any form is beneficial in the long-term.
That being said, my customers have asked me to supply yacon syrup in my health market, so I buy it. I just buy the cheapest organic syrup because it's a very expensive product.