The DELL XPS 13 has an SSD storage medium which is better than most medium processor core notebook PCs that have been available for a comparable time to it. Most notebook PCs that were released around the same time as it 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 portable PCs of this type and age.
The worst storage medium amongst similar types of notebook PC is HDD.
Alternative laptops that have an SSD storage media currently available which you might want to look at include because of it's better review score, the HP ProBook 640 (£770.38).
If the storage medium of this DELL laptop is not good enough for you then you might want to consider the Lenovo X230 (SSD), the HP EliteBook 840 (£529.25) (SSD), or the DELL Latitude 12 7000 (SSD).