If you just take the device on its own functions it is less powerful than it's competitors the supernote and the onyx tablets. It's had pretty bad customer relations due to paywalling a bunch of their features and then walking that back but the build quality is great.
One thing that they did right by pure accident though is give users a root shell into a mostly standard Linux and the community has built tooling that turns this into the most functional of the tablets...but keep in mind this is at the lament of the remarkable team who would rather you use the device as intended.
Supernote is the clear winner among the eink tablets if you use them as intended but many attempts to beg the supernote team to put shell access in have resulted in responses that are at best cautious and at worse condisending.
Until supernote releases the a5x2 (and even then it remains to be seen) this is the best eink tablet
...once hacked that is