Housings:
Sony 300:
The sides are plastic:
https://www.mobileread.com/forums/sho...&postcount=176
I don't like it at all. 2 different materials with slightly different colors. Simply looks cheap and I still haven't figured out what's its purpose. Protection against scratches? But why doesn't have it Sony 600 then? Cost savings? Hope not, wouldn't be "Sony style".
Sony 505:
Very elegant. One of the "coolest" readers out there.
Very ergonomic, too.
Sony 600 and Sony 700:
As elegant as Sony 505. Maybe even a bit more appealing, given its (for Sony 600) choice of colors.
Touchscreen very well thought out.
Sony 900:
New design, very efficient.
The cover (included) doesn't cover front and back, only the front. The back is plastic, "roughened up" for the same "touch and feel" as the front. The back is part of the frame and can be taken down to change the battery.
The front cover is attached to the back and has got the same magnets we already know from Sony 505 or 600.
The expansion cards (both, MS and SD) are inserted on the left side. Both slots are covered by a plastic frontshield.
Sony 900 is way smaller (that's a positive to me) than I'd expected. If you don't focus on it, you won't even recognize the difference to Sony 600.