I've brewed with both sap and syrup a few times to see what I could do with maple. In my experience, sap adds nothing but a talking point- that you can make beer with it. Syrup can add flavor I think, but I've never gotten a discernable maple flavor from using it. If I were to try again, I'd have your sugar-maker friends boil the sap down until its at least adding 15 points per gallon if not more & brew something with no hop flavor or aroma and low gravity- an English mild, Scottish 60/-, cream ale. Stack the flavor deck in your favor if you catch my drift. Have fun with the project- 'tis sugaring season.