From a consumer standpoint, my main qualms when it comes to donations are (1) Control over where my money is spent, and (2) Knowing that my money spent is being put to good use. You guys have the opportunity to knock both those problems out.
Like I said above, transparency is the single most important thing to us, and we spent more than a year establishing our partnerships. If you have any specific questions about transparency and accountability, I am more than happy to field them here. We also have a ton of info on our FAQ: http://watsi.org/faq