Over the last five years Seagate and Hitachi have offered the best price per gigabyte, but which comes out on top for reliability? Well some of the Seagate hard drives namely the 3TB models had a 40% failure rate throughout 2014. Newer 4TB models were much more reliable with a failure rate of only 3%. However the manufacturer that has come out on top is Hitachi with a failure rate of just 1.4% for the latest models. Why is Hitachi so reliable though? Quite simply, Hitachi spend the most on research and development. Hence their hard drives are more reliable by far.
Hitachi perform their research in many overseas laboratories, as well as their corporate laboratories in Japan. In fact it was Hitachi who were really responsible for the hard drive over 50 years ago! So what is the next development for hard disk drives?
Helium filled hard drives are currently being developed by HGST offering up to 10TB of capacity. These drives use up to seven platters, but the crucial advantage is that they are completely sealed. Air filled hard drives require a breather hole to equalise pressure. This means contaminants can get into the chassis causing substantial damage. Helium also provides a lot less resistance to spinning platters, thereby using less power and critically more reliability.
Reference: http://www.datarecoveryspecialists.co.uk/blog/which-are-the-most-reliable-hard-drives