The LifeBook U904 has an SSD storage medium which is better than the HDD storage medium found on most portable PCs of this spec and age. 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 across all laptops of a comparable type and age to the LifeBook U904.
Across similar types of laptop the worst storage medium is HDD.
Portable PCs with a better storage medium that might be worth looking at include the Elitebook 820 G2[pl_2886802_price] (SSD), or the EliteBook 820 G2[pl_2897415_price] (SSD) both from HP.