The Lenovo Flex has an HDD storage medium which is better than the SSD storage medium found on most notebook PCs of a comparable age and type to it. 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 amongst all notebook PCs of this type and age.
An SSD storage medium is the best storage medium across similar types of portable PC.
Alternative laptops that have an HDD storage media currently available which you might want to look at include the FLEX 15, or the Yoga both from Lenovo which is cheaper.
If the storage medium of this 2 in 1 laptop is not good enough for you then you might want to consider the Toshiba Satellite U920t (SSD and cheaper), or the Fujitsu Stylistic Q702 (SSD and cheaper).