Abu Ahmad ibn 'Adi al-Jurjani: He has good hadiths and I hope there is nothing wrong with him.
Abu Hatim al-Razi: His place is among the truthful, and were it not for his concealing the names of some narrators, we would have considered him authoritative when he reports something extra.
Abu Dawud al-Sijistani: No one has troubled me as much as 'Umar has with his concealing of narrators' names.
Ahmad ibn Hanbal: He praised him well and said: 'He used to conceal names of narrators.' And once: 'Trustworthy.'
Ahmad ibn Salih al-Jili: He deemed him trustworthy.
Ibn Hajar al-'Asqalani: Trustworthy, but he heavily concealed the names of his narrators. And once: 'I did not see in Sahih (al-Bukhari) except what he was corroborated on, and what the others considered authoritative.'
al-Daraqutni: One of the high-ranking, trustworthy narrators.
al-Dhahabi: A righteous, trustworthy man. He concealed the names of some narrators.
Zakariya ibn Yahya al-Saji: Truthful, trustworthy, he used to conceal the names of some narrators.
Urfan ibn Muslim al-Saffar: A righteous man, and they did not criticize him for anything other than concealing the names of some narrators. As for anything else, no.
Umar ibn Shabbah al-Numayri: He concealed the names of some narrators, but despite that he is among the most noble of people.
Amru ibn Ali al-Fallas: He is not to be rejected as a narrator of hadith.
Muhammad ibn Ismail al-Bukhari: I do not know him to have concealed the names of narrators.
Muhammad ibn Sa'd, the scribe of al-Waqidi: Trustworthy, heavily concealed the names of his narrators.
Yahya ibn Ma'in: I did not write anything from him. His origin is from Wasit, he settled in Basra. He used to conceal the names of narrators, but there was nothing wrong with him.