F-16E/F aka Block 60 or F-18E/F Super hornet

which of these two is America’s best and probably final developments of the 4th generation era.

infact in terms of avionics it’s even comparable, if not superior to the Eurocanards. But how about to each other, there have been several areas where they compete in the international market place..

features and flaws..

F-16e/f
already using AESA
CFTs increase range comparable to Rafale on internal fuel
already integrated with A2G weapons including PGMs and JDAMs, something eurocanards are still working on.
however the Viper is known to have a weak structure and crash prone

F-18E/F
will use AESA soon
bought in large quantities (much more than b60 or Rafale, built to be maintained and operated very economically). Two engine safety. already intergrated with most of the A2G inventory in the US, good payload
however tends to be draggy and slow.