Abu Ahmad ibn 'Adi al-Jarjani: He is considered truthful and trustworthy by people. I found him to be upright and righteous when he narrated from trustworthy sources. As for what al-Sadi said, it has no meaning, and I have not heard any criticism of Sa'id from anyone. He is considered trustworthy by people, and he was not attributed to any innovation or falsehood. After thoroughly examining his narrations, I did not find anything objectionable about him except for two hadiths.
Abu Hatim al-Razi: He was not very firm in memorization. He used to read from people's books, and he was truthful.
Abu 'Abd Allah al-Hakim al-Naysaburi: It is said: Egypt has not produced anyone more knowledgeable than him.
Ahmad ibn Shu'ayb al-Nasa'i: He is righteous, and I prefer Ibn Abi Maryam over him.
Asbagh ibn al-Faraj al-Umawi: By Allah, were it not for your father and Ibn Bukayr, this one would know what I would do with him.
Ibrahim ibn Ya'qub al-Jawzajani: He had different types of innovations, and he was confused and not trustworthy. Ibn 'Adi said: 'His words have no meaning,' and I have not heard or been informed of any criticism of Sa'id ibn Kathir ibn 'Ufair from anyone.
Ibn Hajar al-'Asqalani: Truthful, knowledgeable in genealogy.
al-Daraqutni: He was among the trustworthy and righteous hadith scholars.
Ali ibn al-Madini: He had different types of innovations, and he was confused and not trustworthy.
Yahya ibn Ma'in: He is trustworthy and reliable.