There are a few things about the Sony PRS - 650 that could use
improving, mainly the same things that are listed on the PRS - 350 review: the lack of styling options, such as changing line - spacing,
margins, font type, etc, all of which requires adding fonts and editing the CSS file of an ebook to change styling; the fact that landscape mode breaks
pages into two sections for ebooks, showing duplicate sentences; and other minor annoyances like having to go through multiple menu selections for certain features and settings.
Nook has
improved from its abysmal 1.5 seconds per
page turn speed — However, it is still behind the Kindle by a fair
margin and it's also behind the new Kindle DX 2.