I must disagree with Ghostdancer though, I personally find Magic Magic casters to be much more likely to be throwing around tons of buffs, and that RPM Mages are much more likely to be using charms to just out and out throw damage downrange.
Absolute effects like Resist Fire and Missile Shield, and cheap low hanging spells like Haste make for great buffing, and Great Haste is a spell that RPM buffing has no answer for, yet slow to cast, expensive direct damage spells get forgotten easily by magic magic mages, while even a modestly powerful RPMist can have a charm ready to deliver a mighty External wallop, or a still fairly mighty save or eat damage malediction charm.
The most awesome RPM / Magic Magic team up I've seen involved RPM and Magic Magic buffing, first the Magic Magic mage used Enlarge Other and Enlarge Object to make the elf swordsman SM+5, then the RPMist topped him off. Then the RPMist used Bestows a bonus to give him extra happy fun per die damage bonuses, after the Magic Magic Mage had made him SM+5 so he had like ST 117 or such for a whole slew of dice to get said bonus
(I can try to find the thread, but RPK at one point discussed the option of converting +2 to +1 per die)
edit - here we go, this thread!
http://forums.sjgames.com/showthread...ighlight=bonus