Even as I was typing it, I noted that their ages are given in multiple sources. The reason we can treat the ages seriously is because, unlike the "scores" each character is given, or the hyperbolic comments made, they have not been discredited. If the scores reasonably measured up to each character, then they'd be a fine baseline to work off. But they plainly don't. They smack of numbers that were written in a time when Kishi had a very different conception of how the manga would turn out, and as a result they now look very silly. Oro having a genjutsu score equal to Itachi particularly shows how ridiculous the scores are. The reason they have a 5 is obvious. When Kishi first was asked for input into the scores he didn't have a clear conception of how powerful certain characters would really be, but then once the scores were given, it was too late to change them in subsequent editions. Therefore Oro, who was supposed to be maybe the most powerful Shinobi on earth when the manga was first written, is given scores that are nearly perfect... but there's no way to adjust that to reflect the error when facts changed. Itachi came along and was so obviously superior to Oro in Genjutsu... but the most he could be scored was a 5... the same 5 Oro had already been given. This makes the scores meaningless.
Likewise, hyperbolic remarks don't count for much, especially not when they plainly contradict other stuff we've seen.
The ages don't have that problem. Likewise, I'm happy for people to quote the map in the databooks, or the reference to what seals each jutsu has (bearing in mind, some people seem to be able to do said jutsu minus the use of the seals).
As to the actual points in the thread:
* I agree, Hanzo was smart to run from Nagato... but if he was really "as strong as the Sannin", he wouldn't have needed to, at least not so soon. Look at Jiraiya fighting Pain... sure, he wouldn't have won, and he wasn't fighting their full strength, but at the same time the running seems premature for a guy who was apparently the most incredible shinobi in the world like some people are making out.
* Hanzo's poison is pretty useless against top Shinobi, as the poster above notes. It'd be especially useless against the Sannin, because Tsunade could almost certainly prevent it affecting her, and ditto Oro. A poison cloud isn't really a great ability against Kage ninja, who can just hold their breath or get some distance, then own you. What good is a small poison cloud going to be against Jiraiya when he jumps atop his giant frog who can jump a thousand feat in the air, and blast you with attacks like this?
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See that? That's Jiraiya burning an area the size of a small village in one shot. Poison isn't going to get Hanzo very far, and some Shinobi particularly are able to overcome it, are immune, or can just regen, etc.
As for him overcoming Edo Tensei, all that shows us is how powerful his will was, not how strong he is. At the risk of paraphrasing Madara again:
"You're going to beat me with your will? Power has nothing to do with will... it's an actual thing".