Hi! I'm new to the forum and I'm sorry if there's a similar thread.
I'm a student and I plan on buying an ereader for reading electronic version of textbooks we use in school.

Most/All of my ebooks is in pdf format. What do you think would be suitable for me?
Formats I would most likely use: pdf, epub, (djvu probably

), mobi would just be for reading novels.
I don't want to zoom in so I'm thinking of converting the textbooks to epub (though I haven't tried that), is that advisable?
Another concern for me is: am I allowed to import my files to e-readers? I have novels saved in epub and mobi formats, i'm wondering if I'll be able to transfer these?
I'm not looking for any additional features (that would just be a bonus), but I would also like for the reader to have a good battery life and not slow when turning pages..
Thank you for anyone who could help me. I'm new to this and I want my first reader to be good.