A d20 or d100 system is easier for players to understand, but usually terrible for simulating actions and results realistically.
Dice pools can be much better at simulating actions and results, but are more complicated for a player to calculate precise odds.
In a d20 or 100 system the success or failure of an action is usually binary, yes or no. In a dice pool system the success or failure of something is usually variable, different levels of success or failure based on the roll or the skill of the character.
I very much prefer the dice pool approach for almost everything.
Dice pools can be much better at simulating actions and results, but are more complicated for a player to calculate precise odds.
In a d20 or 100 system the success or failure of an action is usually binary, yes or no. In a dice pool system the success or failure of something is usually variable, different levels of success or failure based on the roll or the skill of the character.
I very much prefer the dice pool approach for almost everything.