On the fly advice for when you play those -

Learn to love the fireball. Get it. Learn how to place your shots with it properly, aiming for the rear of an enemy swarm until you're comfortable with its area of effect. You don't get a marker that shows that effect zone, so you have to learn how to drop them manually.
More often than not, you'll end up roasting your own crew if you try dropping it in the middle of a melee prior to knowing how to drop it just right.
But once you have it down, you'll be able to fry enemies who are right next to your people, killing them while leaving your team whole.

You'll see the lightning bolt spell. You will be tempted. It's the same level as fireball. Resist that temptation.
Your wizard will be at the back of the group for safety. Lightning bolts travel straight through. They will zap your crew as well as enemies if you don't throw them just right.
They also bounce off walls. Rebound shots still have full power. Using them in any confined space will probably end with your own team getting blasted.

You will see the disintegrate spell. Do not use it. If you disintegrate an enemy, you will destroy their loot as well.
The same thing goes for anything that petrifies an enemy. If you strike them, they will explode into rock chunks, and you get no loot.
Definitely the one with color. It has more personality.