BackBlaze is a large data hosting company. So they buy large quantities of hard disks of different brands and models. And of course when it fails they replace them. The interesting thing is that they publish their statistics regularly, which gives you a good idea of the reliability of the models of the different hard disk manufacturers. They have only kept in the statistics the models that they have at least in 60 copies.
They also compare HDD and SSD failures over the period: SSDs have far fewer failures! That said, you have to take into account the age of the elements: Their HDDs have an average age of 49.6 months, and SSDs 12.7 months. So we'll see over time how well they hold up.

(from sebsauvage)