Ok I've been seeing a lot of people saying ridiculous things about Itachi (making most fans look bad or maybe its only some of his fans that are sensible). So I would like to clear them up.
1.) Itachi can not defeat Hashirama, Minato, or Madara (These are not the only people I think he can not defeat just specific ones that people were saying which stood out to me.)
2.) Sasuke is not stronger then Itachi YET but he will surpass him soon enough
3.) This is the stupidest one in my opinion. Not everybody is susceptible to his finger genjutsu Naruto was freed from it very easily. Also if it was such a great technique he would have used it in more battles.
3.) Izanami is not some ultimate jutsu that makes him invincible, It is actually pretty much useless in regular combat. Kabuto was just the perfect person to use it on and it took a lot of prep time which if he was not Edo and did not have a partner he would have died.
4.) His susano equipped with spiritual weapons does not make him invincible either. He does not have enough chakra to continually spam it and also it has weaknesses as we've seen, such as beneath it, behind it, and it can be broken. Even with Yata Mirror the mirror is only in front of him not on all sides, so if you managed to launch a powerful enough attack from a different angle fast enough it would still work.