The authentic hadith collections of Bukhari and Muslim are excellent in respect to both chain of transmissions and the texts as well as their general utility in that they gave guidance in almost all walks of life. The collections won the praise and acclaim of of Hadith scholars so much that they themselves produced works containing the same Ahadith as found in the collection of both Bukhari and Muslim but with their own independent chains consisting of a lesser # of sub-narrators and called their works Mustakhraj.
Imam Muslim is one of the foremost preservers of ahadith of the Prophet. His book comes second only to Sahih al Bukhari in terms of authenticity according to majority of scholars. It is considered to be better than Sahih Bukhari in terms of organization and repetition according to some scholars of Islam. It is the second in the collection of 6 books called “Sihah Sittah” or “6 most authentic books”. Imam Muslim took painstaking efforts in preserving the words/actions/sayings & approvals of the Prophet. He has mostly used 4-5 narrators in the chain of transmission although there are a couple of hadith containing 3 narrators. Imam Muslim was a very good student of Imam Bukhari and some of his Shuyukhs, although he did not narrate from Imam Bukhari too much, thus reducing the # of narrators.