Having done two LH F outbounds from Europe this year, I cannot agree more that the ground service and on-board food is exceptional (when did BA last do caviar?). My friends were lost for words last month when a Mercedes pulled up on the tarmac to collect us from our LHR-FRA feeder flight and it just got better from there.
That said, the seating on the 747's is a mess if you are travelling solo (all 2 x 2 with no real privacy screen between the seats). LH is also now charging a 10,000 mile 'surcharge' for redeeming BMI miles on LH F rather than any other airlines F.
However, of course, it is swings and roundabouts. The LH business class lounges are not great, especially compared to the LHR Galleries, and of course the LH J seat slopes. I am genuinely surprised that LH keeps increasing the gap between F and J whereas most other airlines are reducing it, none more so than BA.
(And don't get me started on Emirates A380 F, which I did in January and which genuinely redefines what F travel should be, at least on-board.)