I would go for the day flight (1:20). The 11:40pm flight depart late (like most of the night flights) and you only start your meal around 1am because F service requires a lot of preparation by FAs (actually later than 1am as those flights are often delayed by half an hour). To enjoy the meal and watching a movie you need a couple of hours; this is too late for me. Its OK however for Europeans who are still on Europe clock. Also the supper is a bit lesser quantity (but breakfast is plentiful), as most pax do not eat and enjoy a hearty breakfast instead.
The day flight allows for a leisurely wonderful lunch followed by a long nap that gets you readyfor an evening out in FRA.