Okay, Memnoch, no SPAM battles... but Aerie has some very good points!
My favorite Aerie trick is to put healing spells in her Contingency slot. Stoneskins are all mages get, but those aren't a pain in the butt to cast -- healing spells take much longer. Similarly, I live putting two healing spells in a Minor Sequencer.
Okay, Aerie in combat: she can wear the good stuff that a thief/mage can (elven chain) but also she can wear a helmet and shield. With a strength-boosting item (like the Strong Arm mace or a strength girdle), good helm and great sheild like the Fortress, she'll be able to withstand battle, though she won't excell at it.
Bad point: her low Int means that she'll hit her spell-memorization limits early. However, since she has access to all Priest spells, she won't need every Mage spell. For example, she can ignore Animate Dead, Detect Invisible, True Sight, Dispel Magic, Prot. from Fire, Prot. from Lightning, Prot. from Petrification (because of Death Ward), etc.
She's not going to be the one who grabs the Mace of Disruption and Amulet of Power and cleans out a vampire nest... but she could!
As to the inevitable question "what's she got that Vicky hasn't got", the answer is: Fireball, Magic Missile, Lightning Bolt, Greater Malison, Emotion, Melf's Acid Arrow and Minute Meteors, (Minor) Spell Sequencers and (eventually) Chain Lightning, Abi-Dalzim's Horrid Wilting, etc., etc.!
-- Nifft