The Acer Travelmate TMP455-M has an SSD storage medium which is better than the HDD storage medium found on most comparable spec laptops that have been on the market for more than two years. 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 notebook PCs that have been on the market for a similar time to the Travelmate TMP455-M.
The worst storage medium across similar types of portable PC is HDD.
Portable PCs with a better storage medium that might also be worth considering include the DELL XPS 13 ($1,652.41) (SSD).