Essential oils:

• Plant based.
• Not so much variety.
• Expensive.
• Essential oils can have effects on a person, intended or unintended.
• Scents in soap do not last as long as fragrance oils.
• Do not use cinnamon oil.
• You do not need to dilute essential oils with a carrier oil if you use them in melt and pour.

Fragrance oils:

• Synthetic.
• Lots of variety.
• Less expensive.
• Scents in soap last longer than fragrance oils.

Notes:

• Only use soap safe and skin safe scent oils.
• Any oil containing vanilla or vanillin needs either a vanilla stabiliser or a vanilla stable base to keep the soap from turning brown. You could also make your soap a color where more brown wouldn't hurt or be noticed at all.
• Do not use cinnamon oil as that is an irritant.
• The manufacturer should give you a maximum safe usage rate. For the soap itself the maximum is about 1 flat teaspoon of combined liquids/butters/oils (excluding alcohol) per pound/500g of soap base. Therefore your maximum usage rate in soap should be the lesser amount of these two.