I would try the "
Pocketbook 360" for $240.
It has the SD slots and dictionary. Plays mp3 and audiobooks.
I love my PRS-600. If you are worried about "fingerprints" ask yourself this "Do my paperback books have grease and stains on the pages?". Not a problem for me. And if it is for you just wipe them off ( do turn it off before rubbing the touch screen).
If you read much of Terry Pratchett you will want a dictionary. Same if you study foreign languages ( I think that the Pocketbook series have access to multiple dictionaries).
The SD slot bit isn't important unless you like to brag about how many hundreds of books you have on your reader. After all how many books do you read a year? Double it and you'll still have room to add more. And that's without adding a SD card.
The PRS-600 does have a contrast problem because of the touch screen. But if you cahnge the text to
bold it's not much of a problem anymore.
If you do get either Sony readers
DO get Calibre. So much better than the Sony Library software.
P. S. -I belive that there are a couple of people on MR that can sell a Pocketbook 360 to you.