Medjool dates and Barhi dates would probably be best to use as they are so yummy
"Date sugar is a type of sugar found most commonly in natural food stores since it is less processed than more conventional sugars. It is made from dried dates and adds a rich sweetness to recipes, although it will not dissolve when added to drinks. It also does not melt like granulated sugar which can limit its use. It is sometimes promoted as a healthier alternative to brown sugar, although it can be quite expensive."
"There are recommendations that sugar made from dates can be substituted cup for cup for brown sugar, but many find that this causes food to become too sweet. Some bakers who use date sugar regularly suggest instead that you use about two-thirds of the amount of brown or white sugar called for in a recipe to approximate a similar sweetness level."
Credit @ Wikipedia