Finally got my hands on some reasonably priced tonka beans.
As a first timer, this tastes very much like cherries, vanilla, and trident cinnamon gum.
I infused a tiny bit into simple syrup for a few minutes and made an iced coffee with it. To my surprise, it changed the coffee taste. It elevated the sweetness, without making it sweeter. It's almost like msg for sugary foods. The aroma is mild, but it sticks to everything it touches (knives, cutting board, hands).
I made some extract and syrup in the vacuum chamber and tossed some chopped beans in sugar.
I don't think the extract is anywhere near ready to use, but I think it gave it a few weeks head start.