If its real maple syrup, its pasteurized or else you would just have sap. If its the fake stuff, which to me would be any syrup that has more than one ingredient listed, then spend a few extra dollars and get the real stuff, it will have much better flavor.
This year we finally decided to tap a bunch of maples on our property and make syrup. It takes roughly 40 gallons of sap to make 1 gallon of syrup. We have a very rudimentary setup, but for our first year of doing it, things went well. It reminds me a lot of brewing. You have to be very sanitary with everything, and towards the end when you are really concentrating it down, there is a hot break you have to watch for. Still, after 9 hours of boiling over a wood fire, we made the best syrup I have ever tasted, and its making me want to make a maple beer of some sort...or maybe use sap, filtered of course, instead of tap water for an extra little bit of unique flavor.