The NLAW is easier, cheaper, and if it hits probably has similar lethality, but the Javelin is much more likely to hit in the first place. The NLAW isn't really

The NLAW is easier, cheaper, and if it hits probably has similar lethality, but the Javelin is much more likely to hit in the first place. The NLAW isn't really guided: you point it at a tank, track it through the sights for a moment, then fire, and the missile will keep blindly tracking the movement of the tank. So if the tank stops or turns then the NLAW will keep deflecting and will miss. The Javelin actually does have sensors on the missile to track the tank, so it can compensate for changes in direction. Now, when you're fairly close you can probably get away with just momentum tracking, so the NLAW is perfectly fine in many circumstances, but the Javelin is much more likely to hit in any scenario.