I ran a cowardly Mystic Theurge, who was definatly sub-par in combat but I had a fun time playing him.
he was the groups only priest, and the other caster was a sorcerer. He made it to 8th level - the power level ! but the campaign ended shortly afterward.
Running a campain we have had a shadowdancer, Eldrich Knight, Dwarf Paragon (modified) and a True Mage (homebrew)
the Shadowdancer and True Mage had the best powers, the eldrich knight was flavorless, and the Dwarf Paragon and True Mage had the best place in society. The last two were seen as a heros by their society and equal to nobility in rank.
As NPCs they are more common: assasins, alienists, acoloyte of the skin, True Necromancer, Vigilants, Knights of the Shield, and many True Mages have all shown up, usually as villians. Most of them have been better noted for their place in society rather than their actuall powers. only the AoS was more about powers than the titile. This was my intention, as in this game a prestge class was all about the PRESTIGE.