All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger. {C}
Allah preferred some Messengers over others, as Allah Says (what means): {Those messengers - some of them We caused to exceed others. Among them were those to whom Allah spoke, and He raised some of them in degree.} [Quran 2:253]
There is no doubt that Prophet Muhammad is the best of them as he said: "I am the master of the children of Aadam (Adam), the first from whom the earth will be cleft open, the first intercessor, and the first whose intercession will be accepted." [Muslim, At-Tirmithi and Abu Daawood]
As for the Hadeeth that you mentioned, dear brother, it is authentic and it was reported by Al-Bukhaari and Muslim and narrated by Abu Sa'eed Al-Khudri who said:
"A Jew whose face had been slapped (by a Muslim), came to the Prophet and said, ‘O Muhammad! A man from your Ansari companions slapped me.’ The Prophet said, ‘Call him’. They called him and the Prophet asked him, ‘Why did you slap his face?’ He said, ‘O Messenger of Allah! While I was passing by the Jews, I heard him (the man whom he slapped) saying, 'By Him Who favored Moses above all the human beings.' I said (protesting to his words), 'Even above Muhammad?' So I became furious and slapped him.’ The Prophet said, ‘Do not give me superiority over other Prophets, for on the Day of Resurrection all the people will fall unconscious and I will be one of them, but I will be the first to gain consciousness, and will see Moosa (Moses) standing and holding the side of the Throne (of Allah). I will not know whether he has also fallen unconscious and got up before me, or Allah has exempted him from that stroke because of the one he experienced near mount Toor."
Ibn Al-Qayyim said that this unconsciousness will happen on the Day of Resurrection after being resurrected from the graves. He said: "This unconsciousness will happen on the Day of Resurrection when Allah comes to judge between the people and the earth will shine with the light of its Lord; at that time all the creatures will become unconscious as Allah Says (what means): {So leave them until they meet their Day in which they will be struck insensible.} [Quran 52:45]" [End of quote]
As for reconciling between the saying of the Prophet "I am the master of the children of Adam" and his saying, "Do not give me superiority over other Prophets."; then some scholars said that his statement on the prohibition of favoring him over other Prophets was at the beginning before it was revealed to him that he was the best of them. Others said that the prohibition of preferring him was in order to avoid disputes and not to despise (or degrade) one Prophet. The fact of the matter is that he was absolutely the best. It was also said that the prohibition of preferring him was said by him as a way of being humble and modest similar to the saying of Abu Bakr (when he was chosen as a caliph): "I was put in charge of your affairs but I am not the best among you." Yet some other scholars said that the prohibition referred to the preference in regard to the Prophecy itself and not to the Prophets themselves and their overall message or characteristics."
This preference which is given to Moosa does not necessarily mean that he is the best in all aspects. Rather, a Prophet or Messenger may have a virtue or virtues that other Prophets or Messengers may not possess.
For more benefit, please refer to Fatwa 363163.
Allah knows best.