Mail server or anything using RDP.

I've got 9 of the 8TB IronWolfs in my server, and they've been great. The 3 oldest are 4 years old now, and I've grown the size of my array as I could over time, and switched from RAID 5 to RAID 6 for the dual redundancy. Speed is not important in my environment, so I can't speak to that vs WD or Hitachi, but they've been fine for me.