Other than that, there is a lifetime warranty on the black edition, while the core edition has 2 years. <--Not entirely true. ONLY the double fan Black Edition has the lifetime warranty. The reference design BE has a 2-yr warranty. Check that other thread, there's more info there about that.
And they're water cooling friendly. <- I've seen that mentioned before, what's it mean? Aren't all GPUs technically 'water cooling friendly' in that they REALLY like it? lol If you mean that you can water cool it without voiding the warranty...WRONG. There are little stickers on the heat sink bracket that say "void if removed". Sorry.