Sayyiduna Uqbah bin Amr (Abu Mas'ud) (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) said: "The people should be led in prayer by the one who emigrated first. If their emigration is equal, then the one oldest in age. If they are equal in age, then the one who is their best reciter."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 14687