The EliteBook 850 G1 has a better storage medium than most portable PCs of this age and type. This HP portable PC has an SSD storage medium, whereas most portable PCs that were released more than two years ago have an HDD storage medium. Solid State Drives (SSD) store data in semiconductors on a circuit board rather than using magnetic or optical media. Solid State Drives have no moving parts which makes them very fast and reliable.
An SSD storage medium is in fact the best storage medium amongst all laptops of this spec and age.
The worst storage medium across similar types of portable PC is HDD.
If the storage medium of this portable PC is not good enough for you then you might also want to look at the T420s (£972.00) (SSD), or the S540 (SSD) both from Lenovo.