With regards to the PDF query, You should be aware that not all PDF's are created equal.
If you are talking about textbooks / graphically intensive pdf's then dorino's suggestions are correct. Neither device will be great for viewing PDF's and they tend to be quite slow to open.
If however you are talking about novels that have been provided as PDF then it is useful to note that most of these do not have embedded fonts. This means that the fonts are readable as separate to the page rather than being a part or an image. Using the excellent Calibre you can convert these into ePub or any other format you wish. (it does not convert tables and graphics too well which is why textbooks are best left as PDF. Sometimes you will get some odd conversions as it uses character recognition so 'ri' ( r and i ) may be read as 'n' ( letter n ) etc. But on the whole I tend to prefer converting from PDF to HTML as you can get some really odd formatting with HTML files that are a pain to correct.