Who is more deserving of leading the prayer: a man with a beard who shortens his garment and does not smoke, but has limited religious knowledge and does not recite Al-Fatiha well, or a knowledgeable man who recites well, but shaves his beard, lets his garment hang low out of custom and not pride, and smokes?

Smoking, shaving the beard, and lengthening the garment below the ankles (isbal) when not done out of arrogance are sins. If the first imam makes a clear grammatical error (lahn jali) in Surah Al-Fatihah that alters its meaning, then his imamate is invalid and his prayer is incorrect. As for the second, praying behind him is valid, though disliked. If the first imam recites Al-Fatihah well, then praying behind him is more preferable, in order to avoid the disagreement of those who prohibit a fasiq (open sinner) from leading the prayer.