Honestly, from what i have seen and played, i think FNAF 1 is scarier than two. In jumpscare perspectives though. I mean, after a while, if you know that you didn't put your mask on fast enough and Bonnie or Chica was in the room, its not scary when they kill you. Mangle... Isn't even a hard character to avoid, New Bonnie's mask slide isn't that creepy after you have seen it a million times, and all the new animatronics are just kinda stupid. Ballon Boy's concept is good, but again, the jumpscare of Foxy or (other) isn't surprising at all. I do like the idea of winding up the music box, but unless you are afraid of puppets/clowns, The Puppet isn't very scary. You can kinda tell when you are going to get jump scared. In the end, its the stress of doing multiple things at once is what gets me, not the jump scares.
FNAF 1 had more suspense in my eyes. Foxy could peek out of his curtains at any time. Given, it is extremely easy to avoid him, but the fact that he drains power with his knocks is very creative and makes the game more challenging. Bonnie doesn't have too much that is especially scary about him, but when he gets right up to the camera in the storage area, i usually almost pee my pants. Freddy is slightly unpredictable, and the fact that you can only see his glowing eyes half the time is very nerve racking. His laugh and the footsteps from all characters always get me really badly. Chica well... Do i even have to explain her? Her creepy faces, Let's Eat!, her raspy clucking noises when she's behind your camera... You could make a FNAF with just her and the game would still be scary! Of course, FNAF 1 is more about jumpscares, which i prefer. FNAF 2 has the story that everyone wants... And i would probably play it for the story, not the jumpscares.
Don't get me wrong, both games are scary in my eyes, but jump scare wise, i think FNAF 1 has got that part down.
If i wanted something jump-scary, i would definitely either go to FNAF 1 or Slender Elementary/Prison/The Arrival.
(Lol god that sounded like a college essay... And i am such a scaredy cat in real life!! XD)