Spirit-based magic more or less can be divided into two main categories, spirit magic, and spirit summoning.
Spirit magic, has a lot of offensive spells that are similar to elemental magic. It's borrows the power of the spirits when using it. It requires Magic power as compensation.
There's no need to chant in spirit magic spells, everyone can use it if they are connected with the spirits they contracted with. However, to be recognizance by the spirits, it is necessary to be liked by them.
In spirit summoning, it is necessary to be contracted with a powerful spirit. However, to do the summoning a chant is required, though it's easier than the other type of magic. To that extent, there is no need to compare the power. Spirit magic only borrows a portion of the spirit's power, while with spirit summoning it's possible to use the power of the spirit itself. Besides its power, it surpasses it in all other areas. Thus, the power of borrowing is no match for the real thing.
It's very difficult for a user of spirit magic to win against an opponent who uses spirit summoning. Even if the opponent has bad affinity against the other side, he or she would be able to turn over the disadvantage with spirit summoning.