> books on PDF are electronic books. Kindles don't handle them well, but tablets do.
Pdfs on current generation kindles (300dpi) look great, actually, as long as they are computer-generated. Scanned documents can be hit-or-miss, though.
Really? Last I tried, it'd display a page at a time, leaving you to scroll around. Particularly terrible with 2 column layouts like those loved for papers.
Yes, and yes. The viewer automatically crops whitespace in the margins to make best use of display space. Most documents will be smaller compared to the printed version, but still very readable. Anything with the "article" style looks great. Nearly every document with more than one column needs to be reformatted though.
Pdfs on current generation kindles (300dpi) look great, actually, as long as they are computer-generated. Scanned documents can be hit-or-miss, though.