The Lenovo T540p has an SSD storage medium which is better than most notebook PCs that have been on the market for a similar time to it. Most medium processor core notebook PCs that have been on the market for a similar time 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 portable PC's storage medium (SSD) is in fact the best storage medium across all notebook PCs of a comparable age and spec to the T540p.
Across similar types of portable PC the worst storage medium is HDD.
If the storage medium of this medium processor core notebook PC is too bad for you then you might also want to consider the T420s (£1,388.87) (SSD), or the S540 (SSD) both from Lenovo.