Mail items are mainly good for shamans and hunters, but paladins, warriors and death knights can use them too. As in leather, there are two types:
1. Intellect, stamina: For spellcasters and healers. Perfect for elemental and restoration shamans, holy paladins use it too becasue there are only plate shoulders for healing.
2. Agility, stamina: for DPS. Perfect for hunters, but also very good for fury warriors. Death knights, warriors and paladins can use it too, even though it doesnt give them strength, but its good for lvling, as heirlooms give you more expierience gained.