A car is a car, though sometimes it is called an automobile. Regardless, there are expensive cars, middle-range cars, and cheap cars. The expensive cars sure are nice, but sometimes the middle-range or cheap cars actually do what you need and can save you some money. That notwithstanding, cars are generally built of the same components:
Clearly, a high-priced Ferrari will be faster than a Chevette from the 1980s. At the same time, you couldn't use a Ferrari to transport hay, horses, and so on, so it would be cool but rather useless on a farm. What's the point? There are actually a few of them.
The big one is that just as there are many different types of cars, there are many different types of NAC and NAP. Regardless, the solutions will have pretty much the same components, irrespective of the exact solution that is chosen.
Also, there are different cars for different jobs. What you are attempting to accomplish and secure will define the NAC/NAP solution you should use. For example, if your goal is to secure your laptops when users are sitting at a Wi-Fi hotspot at Starbucks or at an airport, will a NAC/NAP device sitting on your LAN actually do that if they don't try to VPN back to your network? No, it won't, and that's why Mobile NAC would be utilized. It's all about using ...