I'll be getting mine about the beginning of October from the looks of it. It will be the 13 inch, since the one I have now is the same one you're trying to sell. I hope the uniboy structure is a little stronger than the plastic on this model, there are hairline cracks in the body near the keyboard, probably from placing my wrists on the body a little too hard, or picking it up.
I hope the battery life is better on the newer one, too. I've heard seven hours. Whereas this model gets about 4 if you're lucky.
This machine is better than my BlackBook.
But the BlackBook was in great shape, I had no cracks, etc... It was a great machine.
You will love the new MBP.