wfalcon

The big advantage with the LV-N engine is it's high specific impulse. This means that it's a very efficient engine. With this engine you get a large amount of delta-v using a relatively low amount of fuel. This advantage is offset somewhat by the fact that the engine itself is rather heavy. This means that for spacecraft with smaller payloads, you're better off sticking with the LV-909. However, if you have a larger payload and you're going on a long journey then this rocket is definitely worth it.