Water has the fastest dash, and you can steer it a bit and leave behind damaging sea stars.
I like how life elements can throw out damaging plants.
light has a good dash move as well.
Earth and fire are pretty powerful, too.
Overall, water is my fav for what I said above. My water knight is OP.
My favs are Life, Water and Undead, in that order. However, I like only a few skills of each... of all elements in general. Life skills are specially awful/boring, that's really bad for me... Undead is not bad at all, but Water is really unoriginal since all water skills are taken from classic skylanders.
Light have really cool and useful skills... but the rainbow stuff ruins everything...