I say go for it! You won't be disappointed.
My husband had an old 700 laying around the house and I picked it up the other day. Couldn't believe the glare/low contrast and that he put up with reading on that for so long. I absolutely love my 650 and my husband loves his as well. And one of my favorite features is the integrated dictionary. I'd really miss that if I had to go back to one of the older models.
I do have the lighted case for my 650--and love it. It doesn't really add that much bulk to the reader--and as pendragginp says it really is much better than the lights in the 700.
dordale