The Last of Us was a better game.
Hard to say. Leon and Ada are pretty much super heroes in RE4. Joel and Tess felt significantly weaker. Leon and Ada would also show up to the fight better equipped for it. Ellie would wreck Ashley, though.
I wouldn't call either one "scary" but I definitely had more tense moments in the Last of Us. Especially because it had more vicious enemies to deal with. Sometimes, RE4/5 felt like turn based RPGs. The enemies would run up, then stop and take STEPS BACK and attack you one at time. In TLOU I even jumped a few times and the game wasn't trying to scare me, I was just that into it.
4 ≈ One