Abu Huraira is a controversial figure even among sunnis. According to Islamic history, he spent 2-3 years with Prophet but narrated highest number of narrations, thousands in numbers. Various sources, even of sunnis, claim that he was severely reprimanded by Hazrat Ayesha and Hazrat Umar on many occasions for telling lies, and was even lashed for forging hadiths by Hazrat Umar. Reportedly, he was also involved in a corruption scandal during his governorship of Bahrain, during the time of Hazrat Umar after which he was deposed. He has also been accused of claiming to be present on occasions, where he could not have been present, giving rise to anachronism in his narrations. Reportedly, he accepted Islam in 7th year after hijra.
However, we may still give him benefit of doubt, because it cannot be established with certainty whether he forged the narrations himself, or other people did and ascribed to him. It is also reported that he used to narrate hadiths of Kaab Ahbar, who was reportedly his friend, and people who heard him mixed both the sources.
Whether or not the stories about him as a person and about his personal character are true or not, we do not know for sure. But it is not his personal character that is important. The issue is with the traditions that are reported on his name. Many of them patently contradict Quran, many mock Prophets, and many are highly disrespectful to women in general. Many of his narrations are too fantastical and impossible to be realistic.
Narrations of Bukhari 5355 and Muslim 2493 suggest that Huraira was perhaps a very talkative person and did not clearly distinguish between what he actually heard from the Holy Prophet PBUH and what he was narrating from himself. We do not know whether he did that knowingly or unintentionally. But there is very high likelihood that people who heard narrations from him also ended up mixing them together.
In the end, we need to remember that Holy Prophet PBUH has left for us the Book of God, which is a complete, perfect, and fully detailed scripture (6:114, 12:111, 16:89, 7:52, 10:37), requiring no further addition by hadiths of Abu Huraira or anything else. Please also refer to verses 45:6-7:
45:6 These are the revelations of God, We recite them to you with the truth. So, in which hadith after God and His revelations do they believe?
45:7 Woe to every sinful fabricator.