If I had a choice between the 2 bikes and had highway travel in mind, I would go with the Ninja 500-why? A few more pounds for stability, 2X the engine size. The 500 ninja engine is a direct decendant of the 450cc engines of the early 80's. Tough reliable bullet proof lil work horses. The only real change was the cylinders were bored out some more, the ninja gets a 6 speed tranny vs the 5 speed on the 500 Vulcan, and the ninja gets a hotter cam-which means faster opening and closing of the valves.
In any case, you needant worry about "flying around" on the highway as the bike, while quite cabable of speeds up to about 140mph is not gonna set any land speed records. It is still only an inline 2cyl engine
