User blog comment:Bloody Bankai/The Plot and Characters in Bleach ( Spoilers inside, please avoid this post if you do not read the manga as well as watch the anime )/@comment-1403595-20091017000705

Well I think Ichigo is potentially the most powerful character in the series, however his lack of experience counts against him a lot. I probably will get howled down for saying this but I think his reiatsu is in excess of anyone else we've ever seen, it's just that he has a lot of trouble controlling it, when he does he achieves amazing things. For example, drawing with Kenpachi in a pure showdown of power, defeating Renji despite loss of blood and injuries sustained, catching Grimmjows hand after Inoue shouted to him and then destroying Grimmjows laceration claws, supposedly his most powerful technique. Yet he is still growing and developing, and so his power has yet to reach his full potential by a long way, so I have high hopes for him.

Hitsugaya is the same, although he would actually have beaten Ichimaru (probably) had Gin not aimed his shinsou at Hinamori, Hitsugaya had encased his arm in ice and then dodged his attack. Aizen we know, relies on his illusions so Hitsugaya never stood a chance. But anyway, I'll expand on this later if others reply.