Some is custom built, some (in their server auction) are just bare consumer-grade ATX motherboards in compact shelves.
We ran two dedicated servers at Hetzner for about three years and had two disk failures. These, too, were consumer-grade Seagate disks, and both of them had been in use by prior customers. All in all it was not a bother and we definitely got our money's worth.
We ran two dedicated servers at Hetzner for about three years and had two disk failures. These, too, were consumer-grade Seagate disks, and both of them had been in use by prior customers. All in all it was not a bother and we definitely got our money's worth.