Much as I'd love to give an honest opinion to help you, people get flamed for it one way or the other, so I'll just state the things that can't be argued with.
Tarutaru have more mp and more int.
Hume have more hp and more vit.
The difference between the two races increases by level, i.e. the higher the level of the character the more of a difference you'll see in stats.
There are about 12 different threads that address taru vs. hume for magic users, some of the most notable in the "summoner" job forums.