ss dad,
We found the advisor very helpful. My son's advisor started working with him the summer of his Junior year. (High School) His advisor was our "pipeline" in regards to what was happening outside of our immediate geographic area. Not being from a "hotbed" of baseball activity, he was instrumental in notifying scouts when my son would be playing in their area. He was instrumental in determining what pro workouts would be valuable to attend and which ones to pass on when there were duplicate dates scheduled for workouts. Once my son was drafted, he was instrumental in being the "buffer" during the negotiation process. Negotiations are not easy. Now, the best part, he placed absolutely no pressure on my son. He didn't care if he signed out of high school or if he decided to use his college scholarship. He simply presented the offers and made recommendations. After my son signed, he was instrumental in obtaining card and equipment contracts and provides a number of other services.
Now, as previously stated, the key is to find someone good. Interview a few advisors, and if they aren't compatable with your son and your family, interview more. Selecting an advisor is a committment on both parts. Good luck to all.