One of the main advantages that I have seen with patents over NDAs is that a patent can offer a competitive
advantage over other companies. For instance when talking about drugs and drug delivery systems, if you have found that your product has worked best with certain processes or certain reagents patents can offer more protection. If other companies try to market a similar drug patents might help ensure that the competitors product does not get on the market or at least it may cause their product to be inferior due to the restrictions. NDAs may prevent the spread of information but does not mean other people and businesses can not figure it out for themselves.