Quote Originally Posted by Thatwarforged View Post
Which one do you think works better with the use of a percentile rolling against your stats like in dark heresy or rolling and adding your stats like the d20 usually does?
Mathematically percentage roll under and d20 add modifiers are identical. The only time it matters is when you have modifiers smaller than 5 percent, but generally these would be so insignificent they are unlikely to actually matter in play.

Personally when I created Heart of Darkness I started out dong percentile roll under, but switched to d20 plus modifier. I find it is much faster and more intuitive, particularly if you need to roll multiple dice at one. For example, if I have five mooks shooting at the PCs I can just grab 5d20 and roll them. That is much easier than finding 10d10, sorting them into pairs, and distinguishing the tens digit and the ones digit.