Why did we burst into action abuse? All I wanted to know is which of these two would have the most 'power'. I remember a regular COer over at Gitp made a comment like "Erudite is high end of Tier 1" and someone around here made a special mention that Psionic Artificer was tier 0
Arcane Fusion, Arcane Spellsurge, and damn near anything else WotC gave to the Sorcerer to make their spells useful is why. Hell, Arcane spells in general are considered the most powerful offense in the game (Divine spells don't have as much BC, but they have some good buffs). The StP Erudite is capable of obtaining every single Arcane spell of 8th level and lower, along with 9th level Psionic powers. Thanks to Schism, Arcane Spellsurge, Arcane Fusion, Linked Power or Quicken Power, you are able to nova without needing to be built specifically around novaing.
Domain spells can be obtained via Arcane Disciple. Other divine spells can be obtained using Wyrm Wizard or Recaster.
The Erudite is able to select their unique powers/day on the fly. If you want a power, sift through your list and just manifest it. That power is now one of Unique powers for that day.
The Psionic Artificer has just as much broken, but the difference is time. It takes time for a PsiArti to craft items, whereas the Erudite can spend 15 minutes in a Planar Metropolis leeching spells off of spellcasters for free (doesn't affect them at all). He then spends 8 hours sleeping and those are now spells known. He is also able to learn a total of 50 powers at the cost of a single level of advancement (next time he levels up, he holds off on the level and spend the XP learning powers). If he multiclassed out at a fairly low level (6th, for example) he can spend the same amount of XP and learn nearly triple the powers.
The PsiArti needs at least 24 hours to craft a single Djore. While there are ways around the time limit, he still has to wait a good deal of time to actually have all of the items he needs. Also the Erudite is next to unaffected by MDJ and similar effects, whereas the Artificer has that as one of his biggest weaknesses (if he's ever caught off guard by one casting of those effects, he's going to be down his most valuable class feature).