I seem to be getting the most reliable emulation with 400mhz overclock and frameskip of 1/2 with Poly, Sprite, and Image frameskip turned off. Leaving those on makes it very buggy. But frameskip does give noticable performance boost even with those turned off.
Name: Twisted Metal
Mode: NTSC
Emulator version: psx4all 20091015
File format: BIN
Frameskip: 1/2 with Poly, Sprite, and Image frameskip turned off
Sound: no
CPU freq: 400MHz
BIOS: scph7502.bin
Notes: Works great so far
Name: Twisted Metal 2
Mode: NTSC
Emulator version: psx4all 20091015
File format: BIN
Frameskip: 1/2 with Poly, Sprite, and Image frameskip turned off
Sound: no
CPU freq: 430MHz
BIOS: scph7502.bin
Notes: Works great so far, this will load without the bios and it does seem a bit quicker
Name: Silent Hill
Mode: NTSC
Emulator version: psx4all 20091015
File format: BIN
Frameskip: 1/2 with Poly, Sprite, and Image frameskip turned off
Sound: no
CPU freq: 400MHz
BIOS: scph7502.bin
Notes: Sprite outline issues as previously mentioned by nine10, and slow movement