The Toshiba Z30 has an SSD storage medium which is better than most laptops of a similar age and spec to it. Most portable PCs that have been around 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.
An SSD storage medium is in fact the best storage medium amongst all similar spec notebook PCs that were released more than two years ago.
The worst storage medium across similar types of laptop is HDD.
Laptops with a better storage medium that might be worth considering include the T420s (SSD), or the S540 (SSD) both from Lenovo.