The DELL XPS 13 has an SSD storage medium which is better than the HDD storage medium found on most portable PCs that have been on the market for a comparable time to it. 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 actually the best storage medium amongst all portable PCs of this age and spec.
The worst storage medium amongst comparable types of laptop is HDD.
There are a number of other notebook PCs that have an SSD storage media currently available which you might want to consider including cheaper portable PCs such as the Tecra Z40, or the Tecra Z40 both from Toshiba or the Lenovo ThinkPad E550.
If you would prefer a notebook PC with a better storage medium then you might also want to look at the DELL Latitude 12 7000 ($675.95) (SSD), or the Lenovo L540 (SSD).