General ACCAWhich papers did people find easiest

I have completed F1 & F3 and will do F2 in August. After that I have to start plotting a route through F4-F9. I will definitely start with F4 as really like legal stuff and have done lots of that before. But after that I am wondering which exams did people find easiest or toughest of the exams F5, F6, F7, F8, & F9? Also does anyone have any recommendations of order to sit the exams. Does one exam flow into another or are they all totally independent? Thanks for any opinions and experiences