Sayyiduna Abu Mas'ud al-Ansari (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) said: "Let the best reciter of the Book of Allah among you lead you in prayer. If the recitation is the same, then the one most knowledgeable of the Sunnah. If knowledge of the Sunnah is the same, then the one who emigrated first. If the emigration is the same, then the one oldest in age."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 14691