Seagates are my "go to" drive, but others will say the same about Western Digital. As long as you don't buy it at a retail store, and buy OEM drives, you are usually fine.
I guess I don't quite understand your use of "slave drive". You could use it to auto-backup, or just use it to hold data, but there are lots of options.
In WinX, you can go to Settings > Storage, and change what drive various folders reside (Documents, Pictures, Videos, etc). With previous versions, you could do the same, but not near as easy.
As for backups, just search for the app "Backup and Restore", and you setup a backup as well.
I have never heard of this farm before, but worth a shot I guess. Render Street, and Raypump are the only ones I can actually vouch for. Raypump actually gives users free daily rendering as well.