This is my first e-reader and it left me very satisfied. Initially, it has a very good screen, you read the letters clearly like printed paper, with the ability to change the font as it suits you. Also, it has dark mode to make reading at night more comfortable. Furthermore, the battery is immortal, it lasts for weeks. Its weight is very light, it doesn't tire you at all.
The only downside is that it does not support epub files. If you have epub books, you need to convert them to azw3 format, which is Amazon's file type. This can be easily done with a converter on Google. Then, to transfer it to the device, you must connect it with a cable to the computer, because with email or through Amazon's website it doesn't allow you (for obvious reasons).
Also, for those who ask about Greek ebooks, it supports Greek normally, there is no problem, however, you cannot find them in the official Amazon store so you will have to resort to other methods...
Additionally, there is some difficulty with reading pdfs as it does not allow you to adjust the size, font, etc., so reading them can be a bit tiring.
Overall, it is an excellent device, if you are a regular book reader you will love it. At first, I had doubts, as I thought it could not replace paper but I was wrong. It has many positives that a regular book does not offer you, such as reading at night without a light, enlarging or reducing the letters, holding it with one hand, and many more.
NOTE: The menu is in English, so if you are not familiar with the language it will be difficult for you.

The screen is very good. Even in outdoor spaces under the sun, you can easily read. It is lightweight and its relatively small size helps for reading while lying in bed or on the couch.
It is not as user-friendly for searching and researching your own pdf files as it is relatively slow. It is ideally constructed for reading books.
There is a huge number of foreign language books available for direct purchase from Amazon at quite affordable prices.