Honestly, don't get either. Stick with HGST or Toshiba brand hard drives. Maybe WD if you get a really good deal.
Seagate has made some really stupid moves as of late. Not only has their quality been terrible (just google ST3000DM001 class action lawsuit) but they've been specifically implementing designs that prevent data recovery in the event the drive has even a minor failure. All of their newer drives are terminal locked, so only their data recovery service can work on them. So they want to sell you the junk drive, then force you to pay them to recover the data when what they sold you inevitably fails.
Avoid Seagate, they're a company who's hopefully going to fail and close up soon.