Welcome to MR, ChefDude.
I've had my 505 since Christmas. My personal choice, in order of preference, is: LRF (it's non DRM), then epub (non DRM) they both work very well on my 505 as I load through the Sony eLibrary and it pre-pagnates or something to open faster.
The LRF is fully justified on both right and left. The epub is only left justified but i don't mind as it still reads well and text enlarges well for me. [I haven't ventured into using Calibre, although everyone says it is very easy to use].
This site has lots of freebies for the Sony (Sony BBeB=(LRF) and epub. They are non DRM) Look on the blue bar up top and on the drop down menu choose either one.
Next, I use the Sony freebies (LRX from the Sony Store which are DRM'd).
Lending Libraries use pdf and epub (ADE) and are fairly easy to use and get on the 505. [I haven't signed up for a library card yet as I have too many books still to be read]. We have lots of members who download books from the library.
Very, very last I use pdf. I really try to avoid it. I just want to load and read.
