Many worked examples here and you can add your own when you've written them:
https://wiki.rpg.net/index.php/GURPS...es_Fan_Netbook
I think magical styles work very well as a replacement to fantasy classes. Fantasy classes have the advantage of niche protection, but the disadvantage of artificiality. Magical styles don't feel artificial because they can't clash with magical reality.
Magical styles can also potentially individualize a setting more easily than fantasy classes, just because the rules of magic can be whatever the GM likes.
One easy trap to fall into is putting too many spells in a style, so that your styles lose their distinctness. Possibly, the best way around this is to allow wizards to learn more than one style. That way, an uber-mage can have a wide variety of tricks to draw on without mastering a style that is crazily broad.