For what it's worth, Charity Navigator gives them 4 out of 4 stars with a 98.33/100 rating: https://www.charitynavigator.org/ein/200049703
Meanwhile eg the American Cancer Society gets 73/100 and spends more on fundraising than WMF's entire budget, so oncologists can snort blow off hookers in Vegas, but nobody cares.
And related to that, some of the practices raise eyebrows.
(For example, letting children play in your freezers and around your blood and plasma donations.)