PDFs are especially great on it...you can enjoy the original fonts, design, and layout in the original (often larger) size.
EPUBs are the weakest because (1) they're not officially supported and (2) converting leads to huge fonts. There's probably a way to fix (2) but I haven't bothered as I find my phone a better medium to read EPUBs.
I bought it specifically for reading pdf papers, and haven't been disappointed. Can't complain about the free 3g, and occasional browser use either if you flash it to 3.2.1 or higher from the kindle keyboard.
- Huge screen for PDF
- Great for technical books
- no backlit means I can read for hours
- decent batteries
My use case: I read mostly non fiction (technical books, business books with diagrams).
I feel like a dinosaur when on an airplane but there is no way I can read my books in these tiny Kindles.
Anybody who has my same use case believes it's time for me to finally upgrade from this old yet trusty DX thing?
I am starting to feel a little Self conscious!
You can read for a lot of hours on a tablet, which is a lot better than Kindle epaper for the types of material you describe. There was a time when some sort of epaper/LCD convergence seemed to make a lot of sense. Today, though, while I prefer a small Kindle for flow of text, an LCD tablet really does win for formatted and graphical content. I still prefer paper for some situations but, given digital, there's really nothing wrong with tablets.
I migrated to iPads once the iPad 2 came out and never really looked back.
I loved the screen though. I'd love to have a DX sized reader with even the processing power of a raspberry pi. Actually, I'd love something with a keyboard cover that let me do emacs in the sunshine, but that's an altogether different story.
I have an ipad as well now, but I prefer reading fiction on the DX.