I would say in D3 the difference between a C- and the highest A+ is, at most, 10% in terms of recruiting value. At D2 it's probably less than 25% and quite possibly not much more than 10% (I haven't played all that much D2, so I'm not sure, but I can say with certainty that it is reasonably small). The main advantage of higher prestige is that players with higher starting ratings will talk to you, players will drop to you sooner, and some will drop or be available for pulldown that are straight nos for lower-prestige programs. But in terms of recruiting bonuses there is very little advantage. A lot of coaches - decent coaches - advise newer coaches never to battle a school with much better prestige. I think this is terrible advice. In fact, given that higher-prestige schools tend to have more readily available options I'd say it's more likely to be a good idea to battle for a recruit with a low-prestige program than an A or an A+ in D2/D3.