Phosphatidylserine is an important chemical with widespread functions in the body. It is part of the cell structure and is key in the maintenance of cellular function, especially in the brain.
Using a phosphatidylserine supplement certainly won't hurt you but I doubt you will notice much from it. It's very wide spread in foods and even if you were deficient in it, your body can make it itself.
One of the best sources of phosphatidylserine is whole eggs. Me personally, I would just eat 2-3 whole eggs each day...