It seems like they use really cheap HDDs. I'm a customer for a few years and in every server since then, one harddrive died. It's not really a big deal when you're using RAID.
For comparison see: http://www.hetzner.de/en/hosting/produktmatrix/rootserver-pr...
Just make sure you don't have anyone on the server (client, etc) running SSH attacks on their core routers or UDP floods, because that becomes a nightmare!