I currently have 2 Exos X20 18TB drives in my array. They were manufacturer refurbs. The drives arrived packaged very well. Both drives passed a full scan and haven’t shown any issues in the 2 months they’ve been up. Sorry I can’t give you a longer history than that but I just took the jump to trying refurb recently.

I’m planning to use them as a source for part of my new array that’ll use 20GB drives. As for special sales, like Black Friday, I have no idea. However they definitely do have sales. I got my drives for $165 and they are currently selling for $190.