Hi, my kid has finally gotten interested in reading

he's been reading paper books and on his iPad, but since he is really getting interested in reading I'm thinking of getting home an e-ink device for his upcoming birthday.
I haven't been following the various devices - are there any that are more sturdy/hard wearing (i.e. metal body etc)? Format doesn't matter, but it needs to be dedicated e-reader, stable in use (no app loading crashes etc).
Thanks!