Grade A maple syrup is produced from sap at an early stage of the season and is lighter in colour. It also gives a lighter taste. Grade A syrups could be consumed directly because of the lighter nature of colour and taste.
Grade B syrups have a strong taste with a darker shade of amber colour. This is mostly used for cooking and baking applications. If your requirement is just a mild flavour that could make your desserts and pancakes tastier then your choice should be grade A maple syrup.