What Are the Virtues of Surah Al-Jumu`ah?
Question

Could you please tell me the importance of Surah Al-Jumu`ah and is it preferred to be read on the day of Jumu`ah like reading Surah Al-Kahf on the day of Jumu`ah.
Praise be to Allah.Virtues of Surah Al-Jumu`ah
There is no particular authentic text which speaks of the virtues of Surah Al-Jumu`ah , rather it was narrated that the Prophet (peace and blessings of Allah be upon him) used to recite it in the first Rak`ah (prayer unit) of the Jumu`ah prayer . 
Ibn `Abbas (may Allah be pleased with him) narrated that the Prophet (peace and blessings of Allah be upon him) used to recite Al-Jumu`ah and Al-Munafiqun in the Jumu`ah prayer . (Narrated by Muslim, 879) 
Authenticity of Hadiths about the virtues of Surah Al-Jumu`ah
It says in AS-Sahih wa’s-Saqim min Fadail Al-Quran Al-Karim by Amal Sa`di (p.81): 
“There is no authentic report from the Messenger of Allah (peace and blessings of Allah be upon him) about the virtues of Surah Al-Jumu`ah. 
There are inauthentic and fabricated reports about its virtues, such as, “The one who recites Surah Al-Jumu`ah will be given good in reward equal to the number of those who come to Jumu`ah and those who do not in the Muslim regions” – narrated by Ath-Tha`labi in Al-Kashf wa’l-Bayan (9/305), via Abu `Asmah ibn Abu Maryam, the well known fabricator and liar. Hence Al-Munawi said in Al-Fath As-Samawi: “it is fabricated.”
However, Surah Al-Jumu`ah is one of the Mufassal Surahs (those in the latter part of the Quran) which the Prophet (peace and blessings of Allah be upon him) said he was favoured with above all other Books and Prophets. It was narrated from Wathilah ibn Al-Asqa` (may Allah be pleased with him) that the Prophet (peace and blessings of Allah be upon him) said: “I have been favoured with Al-Mufassal .” (Narrated by Ahmad, 4/107; classed as authentic by Al-Albani in Bidayat Al-Sul, p.59. He said: “The reviewers of Al-Musnad under the supervision of Ash-Shaykh Shu`ayb Al-Arna’ut said that its Isnad (chain of narration) is good.” 
And Allah knows best.