Ludolf Vaas
"Trust me"
This. Palpatine ftw.A Bunny said:Non-Canon? The Cloned Emperor, y'know who created wormholes and other scary space things like black holes. He could even rupture the force in someone, which is why Luke needed his sister and Mara Jade to fight him. Yet, he couldn't even fight the Emperor directly, he had to be a little rebel terrorist and blow up his SSD Eclipse with super-force energy things.
Although I will admit it's a toss-up between him and Vitiate.
Regardless, it seems clear that the Dark Side is the more overtly "powerful" side of the Force. Sith are usually the better duelists and the most ridiculously broken Force powers are usually Dark Side. But it all depends on your definition of "power". The power of the Dark Side always comes at a physical and mental price. And Jedi don't care much for attaining greater and greater power anyway, so it makes sense that their abilities are less over-the-top.