The HP EliteBook 850 has an SSD storage medium which is better than most notebook PCs that have been available for a comparable time to it. Most medium processor core notebook 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 notebook PCs of a comparable age and type to the EliteBook 850.
The worst storage medium amongst comparable types of laptop is HDD.
Other laptops that have an SSD storage media currently available which you might also want to consider include the Toshiba Portégé Z30-A[plb_2379667_price] which is cheaper.
If the storage medium of this medium processor core notebook PC is too bad for you then you might want to consider the Lenovo T420s[plb_48433_price] (SSD), or the HP EliteBook 820[plb_2697094_price] (SSD).