Since version 2.0, each piece of gear displays a rating in the character window, from grade F to SS.
The grade indicates how many enchants are max level on that gear.
Each gear can have up to 10 enchants, and thus 10 grade: F, E, D, C, B, A, A+, R, R+, S, SS.
For instance, if you have the enchantment affliction at 5/5, then you will have 1 enchant max level and the grade will be E. And so on.
However please keep in mind that having max value enchantments is not that important, the key is to have the right enchantments for your class and to balance the stats of your character.
As such we hope the system can be revamped by the developers in the future to give a better idea of how well a gear is enchanted.