Yeah, I have one that I loved for reading papers. My only gripe was that it gets heavy/awkward for "light" reading at night. I wound up switching to reading fiction on my phone and papers on the DX.

It really is perfect for PDFs. I'm sad they never made an updated version. I've stopped using mine as much after grad school, but I do miss it quite often.

You will open it up, des older the battery and replace it.

Sony has more current hardware in the size range.

I imagine there are ways you could replace the battery. It might not be pretty, but surely it could be done.