I linked the most recent Backblaze report in my first reply in this thread. Here it is again:
https://www.backblaze.com/blog/hard-drive-reliability-stats-q1-2016/

Interesting things about the reports: Despite Seagate having (until this year) the worst reliability, Backblaze preferred to use them because they were cheap, plentiful, and easy to source.

I find this year's report interesting because of the massive improvement Seagate made since 2015. Still, HGST is the king, and has been for quite a while now.