Yes, I just got back a refurbished M8. They give you 3 options:
1) For $30 and a credit card hold of $600, they send you the refurbished one overnight and you have 10 days to send your cracked one in. If there's any other items wrong or you messed up your warranty they auto deduct your card. i went with this option as it was previously my wife's and i wanted a clean start.
2) send your phone in and wait about 10 days for them to fix yours. no costs.
3) i think the other option was expediting the shipping on the repair of your own phone. that was like $25
The phone I got back looks absolutely brand new and no issues so far.
---------- Post added at 07:41 PM ---------- Previous post was at 07:34 PM ----------
Also, HTC was awesome customer service wise. An actual person answered the phone right away, joked about the cracked screen, and had the replacement phone on its way in under 5 mins. Def not what i'm used to with corporations.