The DELL XPS 13 has an SSD storage medium which is better than most notebook PCs of this age and spec. Most laptops of a comparable age and spec to 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.
This notebook PC's storage medium (SSD) is in fact the best storage medium amongst all medium processor core notebook PCs that were launched around the same time as the XPS 13.
The worst storage medium across similar types of notebook PC is HDD.
It may also be worth also looking at one of the alternative laptops that have an SSD storage media currently available including cheaper portable PCs such as the XPS 13[pl_1304263_price], or the XPS 13[pl_1304263_price] both from DELL or the HP EliteBook 840[plb_2446584_price].
If the storage medium of this DELL laptop is too bad for you then you might also want to look at the DELL XPS 13[plb_2601999_price] (SSD).