Silent Hill or Resident Evil?
I know there are a few of you on here who love Resident Evil so I have a feeling on how this one is going to go.
I think Resident Evil arguably wins especially considering for all the shit that RE has in the franchise (Survivor, 6, Operation Raccoon City), it has far more masterpieces in the series (Remake, OG 2, OG 3, 4, 7) in comparison to Silent Hill, which nowadays is probably PT and Silent Hill 2.
As far as horror goes, both go for starkly different ideals, and comparing them is sort of a useless exercise. Resident Evil, for all intents and purposes, is about the horror in limiting the player against a setting and seeing how they overcome it. Silent Hill goes for the horror in the unseen and in warping the perceived reality of the player. Resident Evil and Silent Hill are proponents of claustrophobia, but Resident Evil's is generated through not knowing what's around the corner. Silent Hill's is moreso because the setting feels oppressive, bleak, and foggy.
The mansion in Resident Evil and REmake is a great set piece in of itself as a closed circle that must be progressed through repetition and extermination of enemies. The only areas that truly feel oppressive and bleak are the basement, labs, and underground. However the setting doesn't truly change significantly.
Silent Hill, the town, *is* a character, because it changes and warps as the games progress. Certain things significantly change in the town, and the player more or less, can't do much to reverse it.
With all that said, I think both stand on their own separate but not mutually exclusive merit as horror games. As video games in general, Resident Evil has more to offer with its varied games and interesting ideas that even if they don't stick the landing, they're creatively solid. Most Silent Hill games are inherently similar in the way they are designed, save for PT and other odd projects. Meanwhile, Resident Evil has gone from Static Camera Angles, Dynamic Camera Angles, Over the Shoulder 3rd Person, First Person, and has transitioned from a fairly spooky but campy game to an action-horror thriller, a genuine survival horror masterpiece, a popcorn action flick for a few games before finally wrapping around into a horror survival game in which you are actively stalked by a primary antagonist.
Silent Hill went from well, Silent Hill with static Camera angles, to Silent Hill with over the shoulder cameras (and PT to a first person pov).
Resident Evil went from Alone in the Dark to Aliens-esque, to Army of Darkness, before rooting itself, ironically, back into Clock Tower.
TL/DR: Resident Evil as a game series, but both are equal in terms of horror games.