The Ultrabook 13 has an SSD storage medium which is better than most notebook PCs of a comparable spec and age to it. Most medium processor core laptops that came out 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.
This notebook PC's storage medium (SSD) is actually the best storage medium across all laptops of this spec and age.
The worst storage medium amongst similar types of notebook PC is HDD.