The Pavilion x360 has an HDD storage medium which is better than most portable PCs of a comparable type and age to it. Most 2 in 1 laptops that were launched around the same time as it have an SSD storage medium. HDD is a traditional storage drive which stores the information on magnetic disks. HDD drives are slower than other forms of storage such as solid state drives (SSD) and flash drives.
An HDD storage medium is in fact the worst storage medium across all notebook PCs of this age and type.
The best storage medium amongst similar types of notebook PC is SSD.
There are a number of other notebook PCs that have an HDD storage media currently available which you might also want to consider including because of it's better review score, the Lenovo Yoga.
If the storage medium of this laptop is not good enough for you then you might want to consider the Satellite U920t (SSD), or the U920t (SSD) both from Toshiba which is also cheaper.