Good over all, and good work in raising awareness for different charities.
To the negative review: Rothfuss has seven books (not 2) and works as an adjunct instructor at the University of Wisconsin, Stevens Point (admittedly, an underpaid job everywhere). He's never been too quiet about the latter role.
Not entirely sure why all the vitriol regarding this organization focuses on Rothfuss, as he is not in charge of daily operations (yes, he's the titular--read figurehead--president and the charity rents physical space from him, but he does not run things) and there are many other authors (including Jim Butcher and Kevin Hearne) heavily involved in the charity. I suspect some of it stems from his slow writing on his main book series and people being annoyed about that, more than anything to do with the charity.
Well, member of the general public, with a minimum of effort, and at no expense, you could have examined the IRS forms for this charity and seen what it pays its employees. It does pay a very modest amount of money to several of its officers, but pays nothing, and never has to the "celebrity author". I donate to this charity because I like its causes and the model of picking charities that help people help themselves, and because they often have some great matching offers that let's me multiply my donations. They don't bombard me with requests for money. I find that people who reflexively believe the worst of others often do it because the person they know best, themselves, deserve that exact treatment.
Donating through this nonprofit is a great way to double your impact. Throughout the year I notice campaigns where they will match my donation to charities like the Heifer project (helping people help themselves, by giving them the tools to succeed and become sustainable). I'm sure that they do much more, but this is the part that I participate in year after year. They are a bunch of fun too, with giveaways and jokes. A celebrity author funds the overhead, so your dollars go to the people in need. And since he's a skilled and wildly entertaining author, the blog and updates are so fun to read.
Review from Guidestar