I have a friend who completed F1 to F7 by only self-study (opentuition.com). he is reasonably intelligent guy. anyways hard is relative. if you put the commitment and hardwork you will be fine. He started ACCA in 2013. he is passing each module in one go so far. Howver, he didnt attend F6 exam first time coz he wasnt prepared then. later he tried and passed.