Why raid 1? You do realize that raid 1 is NOT a backup solution, right?
Why green? Unless you're using them for mass storage, do not go green. I got conned into buying a 1TB WD green drive to use as a boot drive - it takes 5 minutes to boot into Windows. It takes ages to do *anything*.
I will never get green again, not even as mass storage. I'd sooner go blue. But if it's the boot drive you're getting this for, then either go black or SSD.
Seagates are currently well known for high failure rates. If you have to choose between WD and Seagate, go WD.