I was in a similar position in May (spoilers, I went with the 580 for reasons lmao). I'd say hands down the Sapphire. IHMO Sapphire is the goto for AMD Cards. I own an original R9 280 Dual X and it still works (just gathering dust in a corner because I have no system to pop it in).
I've heard that their coolers are really good... the same couldn't be said about the Fatboy though. In May I just read a couple of reviews that stated that the card was really loud and generally, unreliable.
If I were you, I'd play the waiting game and go for the Sapphire one. You really cannot go wrong with Sapphire.