Which of the two groups is more deserving of being followed to attain the reward of praying Qiyam al-Layl with the Imam until he departs?

Whoever is able to combine prayer at the beginning of the night and at its end, that is better and brings more reward. As for whoever limits himself to one of them, his prayer with the first congregation until the Imam departs will be recorded for him as having spent the entire night in prayer. Similarly, his prayer with the congregation at the end of the night [will also be recorded as such], and the virtue of praying at the end of the night after sleep is greater. The Witr prayer should be the last voluntary prayer performed.