I'm reserving my vote because I think it depends on your fighting style. If you like characters that get a lot of hit points, you might like a beserker or swordsman. For magic, I would suggest a mystic.
The difference between Mage, Wizard
, and Mystic:
Mage = 4 Casting, 4 Mana
Casting is the chance that you have to cast a spell, and it is required to learn new spells. Sometimes, you will fail to cast a spell if you have an insufficient amount of it. So the mage is a good character for magic.
Wizard = 6 Casting, 2 Mana
Looking at my username, you'd probably think that I'd suggest this one, but actually I don't play the game as a wizard. The wizard will allow you to learn certain spells faster in the beginning, but will come out with less mana, and in Cythera, mana is very important.
Mystic = 2 Casting, 6 Mana
The mystic will result with the most mana, so if you plan on using magic, I'd say that this is the way to go.
It might be useful to know that any character you start with will show 0 mana until you learn magic at the magisterium.
In case you can't tell, I use a magic character mostly. I have tried most of the others, and of them, I was most impressed with a beserker.