I had the experience in the 80's, 90's and early 00's that all my WD drives died quickly, and all my Seagates were fine. Even Deathstars, I'd get a good 4-5 years out of them. But ever since Seagate bought Maxtor, they've been a debacle. The quality now is worse that either had before the merger, and the tech support is horrible - it's been a month and I'm still waiting for a replacement on one Seagate, and it's (now unmirrored) mirror is showing signs of clickdeath. These drives are 3 months old.
As a control sample I bought 8 Hitachi's for a Raid-6 fileserver 2 years ago and it has been running 24/7 with no drive issues. Also a 5-drive array of Western Digitals has only had 1 drive drop in 3 years.
My experience says: avoid Seagate right now. They are by far inferior on quality and support.