When comparing Kali Linux vs PureOS, the Slant community recommends Kali Linux for most people. In the question“What are the best Linux distributions for desktops?” Kali Linux is ranked 38th while PureOS is ranked 54th.
Ranked in these QuestionsQuestion Ranking
Pro Standard pentest tool set
Pro Better than ParrotOS, BackBox for hacking purpose
Contains too many tools for hacking. Those tools are not already included in BackBox or ParrotOS.
Pro Live session distro used for forensics
Pro PureBrowser and TOR
PureBrowser is a modified version of Firefox that comes with security focused plugins. There is also a copy of TOR installed in the OS by default.
Pro You can download and install it, without the need to purchase their laptop
PureOS is available from their site for free for anyone to use, no need to purchase any of their laptops in order to check out the OS which is a tweaked build of the Trisquel distro.
Pro Default install on a free, open source laptop
PureOS is the default OS installed on the Purism Librem laptops.
Con Not intended to be a daily driver
This distro was written for pen testing and security work. It is not meant to be a day-to-day OS (unless that's your job).
Con Very old packages
E.G. Firefox's current version is 61 but Kali linux consists of its 52th version. Though kernel is not that old.