The mage can choose 3 archtypes:
Summoner which leads to Conjurer
Sorcerer which leads to Wizard
Enchanter which leads to Illusionist
Conjurer's have powerful pet's which deal the bulk of their damage. Pet's are 3 types, tank (low DPS, high HP), scout (medium DPS, medium HP), and mage (high DPS, low HP). They can buff their pet into Offensive or Defensive stances, plus give it extra proc power.
Wizards are masters of high damage nukes. They lay devestating damage on their opponents, but then have to worry about the creature turning on them. They definately have the highest DPS of any class.
Illusionists confound and befuddle their opponents, able to stop an attacker in his tracks. They also have party buffs.
There is a ton of group and solo mobs all over the lands. Any class can effectively solo, they just do it a bit differently:
Conjurers attacks with a pet and keeps the fight at a distance. Additional damage spells are lobbed in to help the pet win.
Wizards root at a distance and burn the opponent down.
Illusionists mezmerize the target to not attack while laying on damage spells.
In talking to Illusionists, they feel they are not as strong for DPS than their Conjurer or Wizard cousins. However, when in a group and taking on Epic mobs, they are highly desired to handle "crowd control".
I've completely enjoyed playing a Conjurer, and with the recent revamp and upgrade to pets, we are even more lethal. It is a challenge to manage the pets health and it's action, while watching the battle unfold. In a group of 6, it's like having an extra party member.