Donkey Dude, the 747 has the best trips, altho I may be biased
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The trips are mostly 3 crew with quite a few 4 crew and not too many 2 crew to a wide variety of destinations, east, west and south in pretty equal measure. There aren't any particularly unpopular places.
Also the rest facilities are by far the best with bunks and a toilet in the flight deck
Socially longhaul (as DC says) is very hit and miss. All depends on your crew and the destination, but sometimes you can have a top time when you least expect it (like on statesides due to time diff), and then have dull one one in Cape Town.
Overall life is pretty good, but we could do with an injection of young crew who haven't seen and done it all before.