I finally got a chance to make up a bunch of this syrup and take it around to my family members. Their responses are included below:

Father-in-law: "Mmmm, wow, this is really good."
Mother-in-law: "Yeah, I think it tastes good."
Brother: "What the h*ll is this stuff?"
Mother: "I need a drink of water."
Sister: "Yuck, urine."

And my personal favorite spoken by my father:

"Tastes like burnt hair smells."

So, needless to say, my family will not be serving shagbark hickory syrup on Christmas morning.