Is Saitama the One Punch Man the strongest character ever made?

Everyone knows by now who Saitama is, The One Punch Man. The one thing everyone wants to know is, I'd the strongest character ever created? Now, in my opinion, I can honestly say no, and here why. Strength and Power are two separate things all together. I've thought a lot about this and came up with the conclusion that Saitama is strong, but he's not powerful. 

Again let me explain. If you watch throughout the series, you notice bits of limits he stated or shown he couldn't do. So far he can't fly, yet can fall a great distance without injury, He's speed is not fully measured, he can't breathe in space, and aliens seem to be the only creatures to give him a challenge. Giving those facts we see how would he compare to other characters from well-known comics and anime to see where he stands. First Goku, can he beat him? My answer I see it as being a fair fight with Saitama on top, barely. He is strong I give him that but again his speed is not measured, and with Goku being alien I'm pretty sure he can take a couple of punches before losing his god mode energy and giving up. Saitama won't knock his head off; he's a good guy. Next is Superman, what can I say it's hard to judge this one. Many things can happen in a fight of this magnitude. Superman could take Saitama into space and suffocate him, or Saitama could pluck Superman unconscious before he reaches the outer atmosphere. I see them both getting into it. Superman had never found a person to go all out on and so has Saitama so far. In my option I give this fight to Saitama only because he doesn't care what people think of him... sometimes. He can fight as reckless as he wants and Superman will be to preoccupied with outside calls casualties. 

Do I still think Saitama is the strongest character ever made? I still say no.

He may be weak to Psychics or magic. Maybe Marvels cosmic characters can snap him out of reality. Too little is known about Saitama to judge his true strengths and potential until we get more info on the true source of his power; all these questions will go unanswered. What do you think? Is Saitama the strongest character ever created?