In the interest of full disclosure, my first scary movie was a Nightmare on Elm Street sequel (5, in case you’re curious). So I will admit that it’s possible that I prefer Freddy because I saw him first.
Even so, I’m pretty sure that I prefer Freddy because he’s better.
1) You can’t avoid Freddy the way you can Jason.
Jason (for the most part) stays in a given area. So provided you stay away from Camp Crystal Lake, you’re fine. Yes, there are exceptions—he went on a cruise to New York once and also ended up in space. I stay away from the woods and space. So provided I manage to avoid him in Manhattan (where he almost never is), I should be fine.
But Freddy gets you in your dreams. How do you stay awake forever? You don’t. And even if you manage to wake up before he kills you, you’ll have to keep doing it. He only needs to be lucky once.
2) Freddy looks/acts scarier.
This is especially true in the first Elm Street where Freddy didn’t have many lines. But he’s all burned and he looks gross. Jason, on the other hand, is just a big guy with a hockey mask.
3) Freddy has better weapons.
Okay, I will admit that this is up for debate. Jason does have a big machete (and, in the third one, a pitchfork). But the knife-glove is cooler. And since he kills you in your dreams, he knows what scares you. That is scary.
4) Freddy’s movies are better.
This is a more subjective thing, but as someone who loves scary movies but also good movies, I like things like “plot” and “good characters.” And I have seen every Friday the 13th movie at least two or three times and for each movie, I can name maybe one character off the top of my head (not counting the ones with the last name “Voorhees”). Yes, I’ve definitely seen the Elm Street movies more than I have the Fridays, but even so. Nancy and Alice are much better than Tommy Jarvis.