The Lenovo X220 has an SSD storage medium which is better than most portable PCs of a similar spec and age to it. Most comparable spec laptops that have been on the market for 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 laptop's storage medium (SSD) is actually the best storage medium amongst all medium processor core notebook PCs that have been around for more than two years.
Amongst comparable types of laptop the worst storage medium is HDD.
If you would prefer a notebook PC with a better storage medium then you might also want to consider the T420s[pl_48433_price] (SSD), or the S540[pl_2433540_price] (SSD) both from Lenovo.