I can also vouch for overheating AND failed fans. One card's fans completely died, another card has one fan about to die. I am going to replace them with waterblocks anyways and not really using them for crypto-mining - which brings me to...
No lifetime warranty*
Depending on the serial, some cards DO have the lifetime, but most only have the 2 year warranty as it is in the 7000 series that XFX stopped offering the lifetime warranty. Also, removing that sticker that obscures the heatsink fan screw, will void the warranty (no matter what).
As much as reliable as my XFX HD6950 card is, I am more or less not inclined to purchase any more from XFX (I purchsed the XFX 7970 DD models after being happy with the their HD6950, but reversing my XFX stance with their 7970 usage).
Yep, I also heard that they are no longer offering lifetime warranty so that's definitely a thing to lookout for.
However, when I had overheating issues with my 7870, they sent me a replacement HSF. They told me to replace the HSF myself because removing the stickers does not void the warranty in North America. I used the replacement, temps got worse, then I had to RMA the card. I got a free upgrade to a 7870 Tahiti, asked them if I still have my original warranty. They told me that the
lifetime warranty from my 7870 DD transferred to the new card.
I think you have to register your card with XFX to check if you have lifetime warranty and also possibly to be eligible for it in the first place.
If you ask me, I would RMA your card for a chance at a free upgrade. If you have a 7970 now, odds are you will get a 280X. As far as I know, XFX fixed their HSF issues on the new cards, so it would be something to look forward to.