Included software is indeed version 2.5.
The 2.5 software has 5 font levels like PRS 700 - from S to XXL, note taking since you can sync your reader if you so wish with everything - notes, bookmarks...It has search, but I think the old version had that too.
Other than that nothing struck me as different from before. - edit - actually I think it's faster in transfer to the device and doing stuff on the device from your PC like collections and such - but that may be due to the 700 faster not to the 2.5 Library software
The one thing I do not understand is why they cannot allow you to change metadata inside the Library software the way Ebookwise Librarian did.
I gave away my 500 a while ago since I did not really use it and my in-laws loved it, so I do not recall exactly the screen, but I think 700 is better. It is also wider by a finger or so, more solid and heavier
I activated my 700 with Adobe so the 2 drm pdf's I have - which I bought only because they were so cheap as opposed to buying the print, to make them almost disposable - are readable on it and that was an added bonus.
And to my surprise it's easy to read pdf's the way they are. Some work in reflow nicely when you change the font, others not so, having breaking lines and such, but for those reading horizontally at half page usually works.
I receive pdf e-arcs from publishers once in a while and until now it was a pain to extract text and run it through this or that to make it readable on my 770, but now it's not necessary in most cases
I have not tried math books and such yet but I have high expectations for those too
The back menu and home buttons are your friends, while I turn pages either by touch or by button, though mostly by touch in vertical mode and by button in horizontal since that way comes naturally to me. And I use the touch left to right forward - the default is the other way I think, but you can change it easily
The options button - search, notes, orientation is also very useful and is last so easy to remember in the dark, while the zoom is next to last
I have not installed the manual yet - busy reading, already went through half a novel and several other books to test features
- though I intend to study it for tricks, tips and such