which Hard drive is better??

They are both great products. I like the Seagate warranty as it's 2 years longer but I've used a lot of both and never had any issues with either manufacturer. The Seagate performance specs are slightly better but that doesn't mean a noticeable difference.

What is a good idea is a reminder that hard drives do fail and buying a second one for backup, even if your don't do RAID, is a wise investment.

You wont notice a difference in performance, personal preference here, although as sirmoby states the seagate warranty is 2 years longer.

It's more about personal preference. Both are good drives.

The extra 2 year warranty is nice, but it doesn't cover your data should the drive fail.

Get either one. I've had pretty good history with WD drives. Seagate not as much.

You can get WD drives with 5-year warranties if you'd rather get one of those...