I think it's interesting, but will have to try it out powerwise. I think it has much of the same advantages and disadvantages as the Warlock. Sure you can use the powers at will, but in general none of them are as powerful as a mage or such. Sure, you won't run out at the end of the day, but since the rest of the party has, what're you gonna do, adventure alone?
The Soulborn is more like the paladin with soulmelds replacing divine spells and some powers, than the Psychic Warrior.
The main problem I'm having with it is the summary chart. It lists the basic powers of the Soulmeld, but not the expanded powers. So for instance;
Crystal Helm: +2 resistance bonus on will saves against Charm and Compulsion.
That doesn't really sound that interesting.
The actual power however:
When the Soulmeld is chosen in the morning, gives that.
When Essentia is invested, gives a +1 deflection bonus for each point invested.
When bound to the Crown Chakra in the morning, lends all melee attacks you make the Force descriptor.
It seems a bit more interesting then, eh?
I think the higher level abilities aren't powerful enough, in general. Incarnate Avatar being bound to the Soul Chakra (which you can't do until 19th level, barring feats), gives you Flight, or maybe an enhancement bonus to land speed? That's just silly.
Otherwise, I like the flavor, I like the classes (except for Soulborn being half caster level, I hated that for paladin and ranger too though).
The races aren't bad, if they'd expanded the information on the Mishtai (ancient creators of the Rilkan and Skarn races from the book), maybe they'd have been more interesting.
Azurin are probably the only Human Alternate I've cared for. Drop the bonus skill point and favored class: any, for an extra point of essentia.
The Dusk thingees are bleh.