This question will be near impossible to answer. Any state that produces maple syrup will boast that theirs is the best.
In truth, I believe that the taste depends on the region the tree is living in. The nutrients from the soil have a lot to do with the sap makeup, end result taste.
The sugar house has the job of not only boiling down the sap, but bottling the grade(color) that is most popular or sellable within that region.
I can only equate this question to which state has the best potatoes. It depends on personal taste and state pride.