My wife and I have flown together several times in CX F on both the 777ER and 747. We didn't feel that there was a huge difference, although I suppose one could posit that there's a bit less traffic on the 747 due to F's position in the nose of the equipment.

On the other hand, we try to snag 1A and 2A on the 777 because of the extra privacy it offers (maybe you've already read about that here: http://www.flyertalk.com/forum/15321205-post5.html). My bottom line: which F configuration you're in should not be the main factor in your route decision.

You're going to have a blast.