the contrast is improved in the 600, that's it, the side lights are gone, which is one of the reasons I bought the 700.
poor contrast isn't an issue as no matter where I am I can read it just fine. including the dark. I like my integrated lights.
and I did say hardware wise, and hard ware wise there are only about 3 changes.
it removed the lights and 2 buttons, and that's about it. everything else is virtually the same.
I would like them to port the firmware over already.