Well, the fictitious name is a basic protection so you don't use your personal name in the business. So instead of our name you can use a commercial name. However, this is connected to you personally and therefore you are responsible for any liabilities and even law suits at a personal level. Filing as a corporation gives you more protection and separate the risks from personal liability. This is usually under $1000 so you will sleep better knowing you are protected with a corp instead of a fictitious name.