As the others have said, if you want the best product period, then it's LX F. Nonetheless, olm022 is right on about the value proposition. Here are some reasons why a well-priced A fare in LH F can be preferable:

1) CAVIAR
2) The lavatories (at least on the 747-8) are spacious, have a window, and are stocked with a nice variety of useful amenities. I very much appreciate the Evian spray bottles to cool off while sleeping when the cabin gets hot.
3) The storage lockers assigned to each seat are very convenient.
4) There is something special (to me, at least) about the feel of the large cabin in the nose of the 747-8. I also appreciate that you don't have to walk through a J section to reach F.
5) Great slippers.
6) Ducks.
7) CAVIAR