"To all visitors from Transylvania looking for the head of Voivode Dracula: Yes, we have it. Yes, he's dead. No, you cannot see it. No, he will not return and invade you again. It has been over thirty years, please stop pestering us."
Gender: Male Location: Following the Source of Light.
Just wanted to post a definitive answer. Zero has been stated to be stronger than Mega Man and Bass put together. As far as I'm concerned, he's proved to be stronger, faster, more skilled, and more powerful than Proto Man as well, so this is rather a stomp.
As for Proto Man, I'd say he's Mega Man's peer in power. He's not significantly stronger, and in many portrayals, he's actually weaker in durability.