I do not think any answer is going to satisfy you.
Neither side is more powerful than the other. A Dark Lord of the Sith and a Jedi with the same Midiclorian count have the same overall power in using the Force.
The differences lie in philosophy and application of that "raw power"
As someone else quoted but not fully:
Yoda: Yes, run! Yes, a Jedi's strength flows from the Force. But beware of the dark side. Anger, fear, aggression; the dark side of the Force are they. Easily they flow, quick to join you in a fight. If once you start down the dark path, forever will it dominate your destiny, consume you it will, as it did Obi-Wan's apprentice.
Luke: Vader... Is the dark side stronger?
Yoda: No, no, no. Quicker, easier, more seductive.
Luke: But how am I to know the good side from the bad?
Yoda: You will know... when you are calm, at peace, passive. A Jedi uses the Force for knowledge and defense, NEVER for attack.
Luke: But tell my why I can't...
Yoda: No, no! There is no "why".
Dark Jedi and Sith use their power openly and raw. Those of the Dark Side also wish to control the Force; dominate it. But in the end it is the Dark Side that dominates them.
Those of the Light Side believe and take to heart that it is the Force that guides them; The Force and Jedi Knights are allies...partners, both controlling and being controlled by the other.
Obi-wan: remember a Jedi can feel the Force flowing through him
Luke: You mean it controls your actions?
Obi-wan: Partially but it also obeys your commands.