Just thought that I'd chuck my hat into the ring, after 22 years as a military helicopter engineer I left the daily grind and spent 5 months getting the ATPL ground school done, studying full time at home with BGS notes. I managed to pass all exams first time and averaged 93.5%, this is by no means a reflection of my academic abilities and is purely down to the standard of the BGS course, the notes are excellent but even the notes are surpassed by the quality of the instructors and the feedback questions dished out during the revision fortnights. The revision courses are hard work with 9-5 attendance and then sitting up with feedback stuff until about mid-night but it was well worth it. I cannot recommend BGS highly enough.
As far as what subjects are easiest and hardest, my own opinion is that the weight and balance and the two comms modules are easiest and that meteorology and air law were hardest with the remainder somewhere in the middle.
On another matter, as one of the older trainees out there (41 years old) it was wonderful to read the post from pilotmike who got his first job aged 43 and even shares a christian name with me (surely an omen!!!!!), well done mate if I cam emulate your achievements I will be wearing a smile so big it'll make the Cheshire Cat look like a manic depressive. Its also great to see that a working pilot is taking the time and effort to check the training posts and hand out advice......nice one.