GP Value of Mystic Theurege
I whipped up a little excel spreadsheet showing the GP value of the scrolls equal to the spellcasting ability of a Mystic Theurage vs an equivalent level wizard. 
My methodology. I calculated the value of a scroll of the caster's level for each spell of each character. For example, a Wiz9's 3rd level spells are valued at 3 (spell level) * 9 (caster level) * 3 (spells at this level). I didn't include bonus spells for abilities or for wizard specialization.
Here are the results. Commentary follows.
	
	
	
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Table 1: Total Value at Actual Caster Level
	Level 9	Level 15 Level 19
Wiz	8,100	22,950	31,050
Theur	6,413	23,325	41,925
	79%	102%	135%
	 
 
This is a good metric because scroll value takes into account caster level, which determines both DC and variable effects of the spells. One downside of this metric is that for some spells, this overstates the effect of caster level. For example, moving from caster level 9 to 19 increases the range and is useful for overcoming SR, but doesn't increase the damage of a magic missile.
Following is the same data compiled for scrolls which are written at MINIMUM caster level (which likely understates their value):
	
	
	
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		Table 2: Total Value at Minimum Caster Level
	Level 9	Level 15 Level 19
Wiz	4,400	22,050	34,250
Theur	3,213	26,125	64,525
	73%	118%	188%
	 
 
Interestingly, using minimum caster level shows more benfit for the Theurege, despite the straight wizard having a high overall caster level.
All well and good, but this analysis is essentially static and ignores a very important part of spellcasting, the fact that you can only cast 1 spell per round (subject to haste, quicken, etc). Especially at higher levels, casters rarely run completely out of spells, so it is worthwhile to look at the average value of all spells. 
	
	
	
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		Table 3: Average Value at Actual Caster Level
	Level 9	Level 15 Level 19
Wiz	450	765	817
Theur	229	409	544
	51%	53%	67%
Table 4: Average Value at Minimum Caster Level
	Level 9	Level 15 Level 19
Wiz	244	735	901
Theur	115	458	838
	47%	62%	93%
	 
 This table likely undervalues the straight wizard because, particularly for round-by-round (ie combat) spells, it is likely that the most powerful spells will be cast first. Even though we know the result will be, lets look at the value of the maximum spell castable.
	
	
	
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		Table 5: Maximum Value at Actual Caster Level
	Level 9	Level 15 Level 19
Wiz	1,125	2625	4,275
Theur	450	1650	2,800
	40%	63%	65%
	 
 
Now, one more caveat before interpretation. Doing the above comparison of a straight wizard vs a straight cleric shows that the wizard is seriously underpowered. The total value of cleric spells for a 9th level cleric is 11700/6800 (actual caster level/minimum caster level) which means that wizards have 69%/64% of the casting capability of wizards. Combine this with the fact that we know that cleric have more non-casting abilities than the wizards (d8 HD, Medium BAB, Wider Armor and Weapon Choice, Turn Undead, Domain Power, Spontaneous Casting; although wizards do get bonus feats) and we can reasonably determine that cleric spells are, on the whole, less effective than wizard spells. All of which indicates that the Theureuge is slightly less powerful compared to a wizard than a straight spell-by-spell comparison would suggest.
Interpretation.
So, which table really reflects the actual power level of the Wizard vs the Theurege? Well that depends almost entirely on your campaign style. If spellcasters in your campaign are likely to use all of their spells before they rest and use them for purposes that are relatively independent of caster level (buffs, utility spells) and in non-combat situations, then Table 2 tells you that the Theurege is likely overpowered compared to an equivalent wizard. Whereas, if nearly all spellcasting happens within round-by-round context, then the Theurege is seriously underpowered compared to a straight wizard. Most campaigns are a mix somewhat inbetween.
To me, what is potentially the most troubling about the class is how its relative power grows over time. By all measures, at level 9 the Theurege is underpowered, sometimes very seriously. By level 19 (depending on campaign style) he may have caught up. Of course, my experience with D&D at the extreme end of the level chart shows that lots of things are broken at that level.
My own judgement is that given the Theurege has all the diasadvantages of a wizard (BAB, HD, saves), no feats, the tendancy for cleric spells to be underpowered and the likely style of the games I play in, the Theurege is probably underpowered at all but the very highest levels, where the game breaks down anyway.
Thats my story and I'm sticking to it.
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