We just added last night a really expected feature into Forum Reviews and Comparator: Additional Information Tooltips. Those information are really helpful if you want to know more about a specific feature that you do not understand exactly. Just hover the small icon, and a tooltip containing more information will be shown. A click on this icon will bring you to the full description page of Forum Review Fields.
Note that these icons are also available in the Forum Comparator.
As you could notice, every fields have not a description, sometimes because they are sufficiently understandable, and sometimes because it is not complete yet. So, do not hesitate to contact me, through the Discussion Forum if you want to know more about some unclear fields.