I'm a few years away from applying, but I am also interested in the NHSC program. From my understanding, the program is not very competitive for clinical psychologists as there were an abundance of unfilled positions due primarily to lack of applications. However, funding has also been an issue for the past few years for obvious reasons. The repayment for placements in an area with a HPS (health provider shortage) score of 14 or above (which means that very few if any providers are there) will get the full $25,000 per year in loan repayment, and if if the provider remains after two years the repayment is $35,000 per year or until the loan is payed off. If the HPS score is below 14, the amount will be less than the 25g (proportionally, I think, to the amount of need). Also, clinical psychologists must be licensed in the state they apply to participate in the program. I would go over the website thoroughly to see if I am misleading you...its been a few months since I've checked out the site. If you browse the site long enough, you can get a good idea of the application process and the overall pros and cons of the scholarship.
I'm primarily interested b/c I want to work in a rural and underserved area (not really for the money if you can believe it), so its likely that I'll participate even if I dont get a placement with the full repayment amount.