I found the monsters in Silent Hill 3 to be much more terrifying.
The monsters in Silent Hill 2 just made me feel sick. Though of course they were still 'terrifying'.
That's a pretty good way to put it actually. Silent Hill 3 monsters were more terrifying in that they more hellish looking. They seemed more demonic than the Silent Hill 2 enemies. That could very well be the atmosphere of Silent Hill 3 causing them to feel more demonic. The enemies from Silent Hill 2 disturbed me more. They weren't terrifying as much as they were just odd, abstract, and very gross. Their design and concepts, I personally felt, were more disturbing than Silent Hill 3's monsters. I guess this is how I'd put it. I was scared to attack Silent Hill 3 monsters because they seemed like very dangerous monsters. They were big, loud, and incredibly violent. Some of them were also very fast, which made it feel as if I was pursued by some predator. However, they could be (relatively) easily killed. I was scared to face Silent Hill 2's monsters because they were so weird and gross. Half the time they wouldn't even die on me, they'd shamble along the ground until I stomped on them. It was just disturbing. Like watching maggots crawl about in decomposing flesh. Again, the Abstract Daddy still freaks me out.