Has anybody used the Arcane Order and their mages? These guys are detailed on College of Wizardry for 2E and included in Complete Arcane in 3E.

I love the idea of the Spellcrux, and I'm curious as to actual player experiences. The Spellcrux is a tool that allows members of the order to cat up to 3 levels of utility spells per day. They are required to pay back any spell levels before using it again.