Preface: yes, absolutely, all the props in the world to this guy for doing something so thoroughly incredible and selfless and rare for the benefit of humanity. Even if I had the means, I know I'd never have the guts to do something so amazingly heroic in as extreme a way as he did.

That said (i.e. time to be the irritating pedantic little asshole, but I think it's a genuine enough question about the purpose/execution of philanthropy)... does the anonymity really warrant extra props? We know that the guy gave away essentially all of his money; does the anonymity of the individual donations really make it more selfless? If anything the headlines "Feeney gives $100M to cause X" and going on TV to talk about it etc. would likely bring more attention and donations to X, which I assume is why Bill Gates and others tend to do things that way.

Edit: ok, I've just figured out from other posts that it basically wasn't known beyond a small group of people that he was giving away most of his wealth. I didn't realize that (although it's also my first time hearing of him). I agree then, he really did spend the bulk of his life being pretty much truly anonymous and that does deserve extra props.