While raw agave isn't my first choice to sweeten recipies, I use it in small amounts (1 Tbsp per day or less] usually to offset a bitter or sour taste. I use dates or raisins for smoothies or dehydrated products to sweeten. But sometimes you need a liquid sweetner as when taking tumeric with pepper and olive oil. Honey isn't vegan. And maple syrup isn't raw. There's raw agave. Just a little bit, 1 tsp is fine. At that dose, it won't touch your blood sugar or triglyerides. The dose is the poison. One aspirin is relief, 1/4 of the bottle and you're on your way to the emergency room.
Why use it at all? I have created amazing dishes using apple or orange juce. Bananas are a great sweetener. Carrot juice! And don't forget the number one sweetener, medjool dates! They are raw and sweet as sugar. Agave is processed and terrible for you. It sickens me to see people use cups of it! I say moderation is key unless you know better!
I guess some of these thicker sweeteners are needed for raw sweets and cakes to thicken them up.
I haven't used yacon but like the sound of it if i ever was to make any raw gourmet meal. I don't really eat anything like that, i tend to keep my sweetness reserved for fruit. I have also heard good things about coconut sweetener.