I don't think so there are major differences between the seats.
Since the 747 cabin has 2-2 layout the pitch is bigger by couple of inches (many 10-15 cm) so that pax on window side can exit without disturbing one on the aisle.

There is a special IFE on 747 from the on board library (BTW: the same library is used on PrivatAir operated all C class flights to/from US). On Airbuses there is all cabin inclusive IFE.

F section on 747 in on the upper deck making is feel more private. But on A340/330 there is large buffet area in front.

Also I found bathrooms on 747 larger (and with windows).

Any special / preferred seats. I don't have one, but I'd advise to avoid:
on Airbuses: row 2 on the right side (2G & 2K) as simply they may run out of meal choices by they time trolley reaches you - yes it happens more and more often these days.
on 747: row 81 (1strow) and 84 (4th & last on the right side) H & K bathroom is either in front or behind, also exit row 83 is hit or miss - sometime FA park carts during meal service just in front of you, right side has a min drink buffet and left FA’s emergency seats.

Let us know what are your impressions after your flight.