Tim,
There are some parents and players who post here who have been very successful in college and beyond. I think the overwhelming conscensus is that recruiting services are not useful and many feel they are a waste. I think most posters feel you are much better served by attending showcases and contacting coaches directly. In your case, you may well want to also look into trying to have your son attend the Stanford All Star camp. I cannot tell you the number but there are plenty of players who made the contacts with their now college coaches at that camp. It has gotten a bit pricey but still much less than a service. And with the price has come more coaches and more exposure. Good luck.