With a realtor you will have the home exposed to more buyers. Most buyers are already working with a Realtor. It also depends on the area in AC. I know the city very well if your in a good area it should move quikly. It also depends if its priced right. Call me if you have any questions.

Private investors usually do have a Realtor that they work with. So by working with a Realtor, you get the best of both worlds. The exposure to the general public and to the investors. In the Atlantic City area, it is important to find a Realtor that has excellent internet presence, since it is a "resort town", your buyer may come from most anywhere in the country. As a Realtor in Atlantic City I have had buyers contact me from Florida, Arizona, and California.

For a quick sale, right pricing is key. A Realtor who knows how to price your property for quick sale should bring you more money than a private investor. Price it at 5-10% less than the next comparable property and reduce every 2 weeks if necessary. The private investors will take notice as well as the general public.
Good luck!