CFA is not superior in toughness when compared to ACCA or CIMA the only thing making it "HARD" is the volume of the syllabus , But a six month study is enough to cover them all .There are some papers in ACCA which has low passing rates as about 29%.

I myself did CMA (IMA USA) completed exams & passed now in planning to go for either ACCA or CFA.

If you have commitment,confidence and hard-work you can pass it all in one go!!

best of luck