We were at a Mennonite store last week and they had some kind of maple syrup they were really proud of for $54/gallon. It sounds expensive to me, but I really don't know what it's going rate is.
Believe it or not that's actually a pretty reasonable price for quality syrup. The best stuff out of Vermont is around $70 a gallon + shipping.
They changed the grading system about 5 years ago. Previously the two darker grades were "Grade A Dark" and the super dark "Grade B". Now they've combined those grades and the term you're looking for is "Grade A Dark Color/Robust Taste".
You could always get just a pint for $10-$15 to give it a whirl. I'd sell you some of mine but my kids would riot!
I think once you try it you'll never go back