Sorren said:
Damage is the Only Common Ground.
To compare the two, the only true real basis for analysis is damage output. The usefulness of other powers and spells is too dependent on other factors such as the DM's style, the environment, etc, and therefore can’t be taken into consideration here.
It's one way to compare, but certainly not the only one and surely (IMHO) not the best one (especially not, if the numbers are flawed, which easily happens, not to blame you there, just the system

). I believe the best way is to simply compare spell/power levels at the same scaling/augmentation level, as I have tried on page 3.
Why? Because it doesn't focus on single spells/powers, which by themselves could (and most certainly will) not be fully balanced among each other, or single hypothetical situations only; it focuses on the potential, which can be brought to bear, be it damage, utility or whatnot. It's more generic and includes many more situations than simple damage dealing ever could. Still it is accurate, since spell levels and caster/manifester levels are the base for the whole system and very much compareable.
The crux of this comparison is the following:
An x-th level spell of y-th caster level (but not higher than the cap) has about the same effect as an x-th level power augmented to y-th manifester level.
The powers are often more flexible by themselves (especially when looking at the kineticist powers, of course), but the actual effect will be and should be
roughly the same. The flexibility itself is not covered here, however. The power also costs more effectively, because "scaling" has to be paid for, but this cost is obviously included already, if you compare the augmented power and look how many of those can be manifested compared to scaled-up spells. But do not forget here, that quite a few powers are available also, which have their full effect at minimum augmentation level (in fact do not even have any augmentation in most cases, Fly or Metamorphosis are two of those), so it is not needed to fully augment every power (duration and range do scale for free for psions in the same way as they do for the sorcerer).
With this in mind, the number of spellcastings/manifestations per day is being compared.
I believe, that in this comparison, the sorcerer and psion come out about even... so far. The sorcerer will win in the endurance department (additional low-level effects), obviously, while the psion clearly wins in the raw power department (more powerful effects in a short time). I consider the latter to be more important (which the "Mystic Theurge problem" effectively demonstrates, who suffers greatly from the lack of high level effects, which is not fully compensated by the huge amount of low level effects they have until they reach very high levels (and by then have much, much more additional low level effects than the sorcerer has over the psion)), but that's just an opinion like any other. All in all, I think it's ok up to this point and neither class is at a considerable advantage yet.
Now, if they are about even up to this point, if you look at what is left, because the above is not the whole picture yet, the psion has such a clear advantage there, that it's not even funny.
+ usually higher save DCs on augmented powers (further increased by psionatrix)
+ faster access to higher power levels
+ more "effective spells" known (one power includes more than one spell in most cases), much more high level spells/powers among those (and on top of that the ability to swap all powers, skills and feats out
completely at an XP cost)
+ much higher flexibility and the ability to manifest more high level powers or a huge amount of low level powers
+ many powers have built-in flexibility, which similar spells lack usually
+ no need for many metamagic feats (Heighten, Still, Silent, Energy Affinity mostly)
+ Quicken Power
+ Swift and immediate action powers
+ no verbal, somatic, material components (grapple, silence)
+ bonus feats
+ better feat choices
+ better skills (more effective skill points and better class skill list)
+ armor
- lack of good party buffs, often powers are personal only
- weaker base to pick powers from, there simply are more spells out there
- more restricted by discipline lists (tho, since they have plenty more feats (bonus feats and non-dependancy on metamagic feats), this can be circumvented with Expanded Knowledge to a degree)
- psionic focus issues (tho the feats (Psionic Endowment/Penetration most importantly) are better in comparison and the focus issues can be circumvented to a degree)
If I have missed something important here, please point it out, I'll gladly add it to the list.
Bye
Thanee