Sugar-free is a claim about one ingredient, not about the food. Take sugar out of a dessert and something has to replace what it was doing, which was sweetness, browning, moisture and bulk. Plenty of recipes replace it with fat and never mention it.

The other thing you have probably already met is the aftertaste. Erythritol pulls heat out of your mouth as it dissolves, which is physics rather than flavor, and it is why a sugar-free cookie can taste faintly of a mint nobody added. Allulose does not do that and it browns properly, but it holds moisture, so things made with it stay soft whether you wanted soft or not.

So every recipe here names its sweetener and says where that one fails, and the fat is printed next to the calories. If you are deciding between them, start with which sweetener to use.