agree with lee. the main one i had a hard time with was gen nav. not my best subject. needs quite a bit of work but dont forget the other exams.
met has alot of stuff in it to cover but for me its just boring so took longer to learn.
Principles of flight is another one that u just want to get over and done with.
flight planning is also another big subject but very very simple. alot of answers are in the jeps which you take in anyway.
performance is pretty simple once you get the basics in. not much more difficult than the ppl graphs.
instraments was pretty interesting some good stuff to know
air law and ops was loads and loads of numbers and facts. i was quite lucky as the tutor had a good way of teaching it.
mass and balance very simple to learn. infact i just spent 2 days revising the subject as there are only like 4 things to remember and i got 100%.
IFR/VFR comms a bloody waste of the 1 hour i spent revising them and the 62 quid i paid for EACH, just for the privilage of sitting in a room colouring in boxes for 3 minutes...