Unfortunately to admit I've only had one Seagate fail on me in all my years, and it was just a bricked firmware error I was able to fix, that drive never failed again and to this day lives on. Since that day it took me until two years ago to give Seagate another try, bought one of the new 4TB drives and it has been in constant use since, I put enough faith in them to buy 3 more and RAID 5 them, at least if one goes I won't be loosing much, except the time to rebuild.
As for WD, I had a 640GB Black fail on me 4 years in to the warranty, ironically It was the only drive I had ever bought an extended warranty for, lucked out and they replaced it with a 1TB unit which had since been reliable, fingers crossed it last. Presently I have two 2TB Greens that are no longer usable, they work, just the read/write speed is none-existent at this point making them as good as paper weights, but for Green drives I had in a 24/7 use scenario I can't complain, ironically they were among the newer of my 2TB Greens...