Reward for Memorising Quran
Question

What is the reward for becoming a Hafidh?
Praise be to Allah.The Elevated Status of Memorising the Quran in the Hereafter
Whoever memorises the Quran and acts upon it, Allah will reward him and honour him greatly for that, so that he will rise in status in Paradise to a level commensurate with what he memorised of the Book of Allah.
At-Tirmidhi (2914) and Abu Dawud (1464) narrated from `Abdullah ibn `Amr that the Prophet (peace and blessings of Allah be upon him) said: “It will be said to the companion of the Quran: Recite and rise in status, recite as you used to recite in the world, for your status will be at the last verse that you recite.” This Hadith was classed as authentic by Al-Albani in As-Silsilah As-Sahihah, 5/218, no. 2240, after which he said: 
Note that what is meant by the “companion of the Quran” is the one who memorises it by heart , as the Prophet (peace and blessings of Allah be upon him) said, “The one who knows more Quran should lead the people in prayer,” meaning the one who has memorised the most.  The differentiation in status in Paradise will depend on how much was memorised in this world, not how much one will recite on that day as some people imagine. This clearly points to the virtue of the Hafdh who has memorised the Quran , but that is subject to the condition that he memorises it for the sake of Allah, not for worldly purposes or financial gain. Otherwise the Prophet (peace and blessings of Allah be upon him) said: “Most of the hypocrites of my Ummah are among those who have memorised the Quran.” 
The Virtue of the Quran Memorizer
Concerning the virtue of the Hafidh who memorises the Quran , Al-Bukhari (4937) narrated from `A’ishah that the Prophet (peace and blessings of Allah be upon him) said: “The likeness of the one who reads Quran and memorises it is that he is with the righteous honourable scribes. The likeness of the one who reads it and tries hard to memorise it even though it is difficult for him, he will have two rewards.” 
For the Hafidh who has memorised the Quran , praying Qiyam Al-Layl is easy. And the Quran will intercede for him on the Day of Resurrection, because the Prophet (peace and blessings of Allah be upon him) said: “Fasting and the Quran will intercede for a person on the Day of Resurrection. Fasting will say, `O Lord, I deprived him of food and desires during the day, so let me intercede for him.’ The Quran will say, `O Lord I deprived him of his sleep at night, so let me intercede for him.’ Then they will both intercede for him.” (Narrated by Ahmad, At-Tabarani and Al-Hakim; classed as authentic by Al-Albani in Sahih Al-Jami’, no. 3882) 
It should be noted here that there is a weak Hadith that is quoted concerning the virtue of memorising the Quran. This Hadith says, “The bearer of the Quran, if he regards what it permits as permissible and what it forbids as forbidden, he will intercede for ten of his family members on the Day of Resurrection, all of whom deserved to enter Hell.” (Narrated by Al-Bayhaqi in Shu`ab Al-Iman (The Branches of Faith) from Jabir; it was classed as inauthentic by Al-Albani in Da`ief Al-Jami`)
And Allah knows best.