Though I used Scarfaces System for many years, it seemed to glitch at times when PCs had either a wide spread of levels in their party, one or more was level 20+ or defeated foes had CRs well above the PCs. I never could pinpoint the exact causes and glitches were irregular. Still it was better than most systems I'd tried .... that is until Blasco's Fair Kill came out. It shares many of Scar's funtions and pulls from other systems too. I think it's the best available to date and the easiest to set up and tweak.
http://nwvault.ign.c....Detail&id=3630
Try it, you'll become a fan too.