Which is better: Night vigil prayer or seeking sacred knowledge, knowing that I am more active in seeking knowledge?

It is best to combine night prayer (Qiyam al-Layl) with seeking knowledge. This was the practice of the righteous predecessors, because Qiyam al-Layl aids in acquiring and solidifying knowledge, and through it, Allah grants the servant understanding. Allah the Almighty says: "O you who have believed, fear Allah and believe in His Messenger; He will give you two portions of His mercy and appoint for you a light by which you will walk and forgive you; and Allah is Forgiving and Merciful." (Al-Hadid: 28).