It's completely a personal preference. Some people want to read everything with the same settings and their own chosen font. Other people might like to actually read the book in the font that the publisher recommends for the story. When I bought an ereader my main concern was I might miss the specific formatting that you get in some books. And some fonts are really well chosen to suit the story – and I must say I do miss it in the books I read. Up to now, I have stripped the books of all font settings, but only because the ebooks I read weren't well formatted by the publisher: not as much attention had gone to the layout and font as to that of the paper books. Coincidentally the first ebook I found with really nice font and layout formatting was from a new book, and I do not plan to strip that of its font. So who knows, maybe new ebooks might get more attention.