I was looking at these last night and was thinking they are a pretty cool item. If I understand them correctly you expend an arcane spell of an equal or higher level of the spell you want to use from the staff. This being said it becomes a valuable item for partial arcane spell casters. Say a Beguiler with a Runestaff of Evocation now has a pretty good offensive cabability. What drawbacks am I missing?
The spell has to be on your spell list for you to cast it from a runestaff. That makes them useless for beguilers, dread necromancers, and warmages.
They are geared to spontaneous casters with limited spells known, such as bards and sorcerers.
Ah I knew I missed something somewhere. Thanks
Runestaves are also useful for wizards. Even the most prepared wizard can find himself/herself with the wrong spells prepared for the day. Just whip out the necessary runestaff, and spend a un-wanted prepared spell to power its use.