The new F seats are installed when the Skybeds in J are installed. Most/all kangaroo route 744s have been refitted but only 1 or 2 trans-pacific have been refitted ... so chances are you will have the old tired worn-out F seating. The new seats are a noticable improvement being the next generation of the same seat and similar to BA F (but better). The first seats in the middle and also in front have a narrower ottoman (similar to BA F size), while the other seats have a wider ottoman -- this is only an issue if you are tall, say over 6 foot 6, in which case the wider ottoman allows spilling into the aisle while the narrower does not. All the trans-pacific flights have indistinguishably the same service and loading (it is at the whim of the daily load) though MEL-LAX is often fewer pax in F so if you really care you can route via MEL on QF93/94.