My son signed up when he was a freshman because a local D1 used it instead of recruiting questionnaires. The Varsity baseball coach liked it so much he had all the varsity kids create profiles. He's pretty good about updating his assessment of players a few times a year. Like someone said above, you can be linked to more than one coach and all coaches can provide an assessment. The coaching assessments cannot be seen by the player.
My son has a few college coaches following him and he's a Sophomore. A coach has even contacted the varsity coach about my son. We only use the free version right now.
It's neat because you can see what level of coach is looking at your profile (i.e. NCAA D1, D2, JC, etc) and also see when your teammates meet coach search criteria. You have to pay if you want to see the specific coaches/schools that are looking at your info or to see what schools the site has matched you with. Your profile can have as much or as little as you want. My son has a lot in his profile, including transcripts. We'll also be linking video when it's done.