Thanks for providing even more detailed info about the Kindle fonts. It appears that despite its negatives, the Kindle just might be the best eBook device for those who are visually impaired.
Thursday night, I came across a good example of Sony's discrepancies with their fonts. "Oliver Twist," by Charles Dickens, part of Sony Connect Classics (formatted by Sony) is full of formatting errors, making it impossible to read. Individual words are connected as one word, no spaces after periods or commas, to name a few. In comparison, the illustrated version of "Oliver Twist" uploaded on MobileRead is in a nice bold font and does NOT have these formatting errors. It is a pleasure to read.
Why on earth Sony doesn't take advantage of the entire Reader screen and either bold the fonts and/or make them larger just doesn't make sense to me. Simply put, they are fools.
Just an aside, because someone in this forum recommended blackmask.com for public domain books, the automatic formatting they use on their eBooks is a thin font and very difficult for the visually impaired to read. On the positive, they do have some VERY RARE things available, including magazine articles from the 1800s!