Most complicated seems to be synonymous with best to many people.
Look at the wartime stuff. Panther tank for example had a tendancy of killing its own transmission.
At Kursk:
184 Panthers deployed
44 removed because of mechanical failure
56 removed because of damage caused by AT mines and enemy fire
58 Panthers completely lost by the end of Citadel
-By Day 3 of the operation, only 40 out of 184 Panthers were operational
-By Day 6 of the operation, only 10 out of 184 Panthers were operational
Then there's the west german G11 rifle. Literally made with german space magic clockwork or some bull****.
Production aborted because of both reunification and excessive complexity.
I guess the german engineering is the most advanced or whatever in these cases. I mean even the cup holders in my polo are over the top, cool, but unnessecerrily complex with lots of folding bits that retract.
Not really the best though.