In order from hardest to easiest

Far

REG

BEC (just because it is so boring to study)

AUD

I would say that REG was the hardest section for me.  Specifically the Tax part.

Which one is more difficult and requires the most study time, REG or FAR?

I wasn't sure where to post this so I posted it here and in the FAR folder too.

Thanks!

For me, REG has been by far the hardest. My tax background is very weak (didn't learn it well in college), and law is just a difficult area.

It really depends on what your strength is. In general, Reg and Far are the 2 hardest.