Mine arrived on Friday, too, I love it! Yes, it is so much lighter than the 505 and I like the black finish. I have never seen the 600 so I do not know what the screen looked like but the 650's screen does not look that different from the 505's one, IMO - they are both crisp and the only difference I can see is that the ink on the 650 is darker and that makes it easier to read, and maybe it also makes it look a bit sharper.

The only thing I miss so far is the Menu button which also acts as a Back button on the 505; now I have to press at least two options to perform the same function. There is a back function on some screens but not all.

The things I like so far is the darker text, the landscape mode (especially since it means that I can change the pages with a button on the left side), the faster changing of the pages (you can really tell the difference here!), a better choice in font sizes (the Medium font is huge compared to the one on the 505) and the dictionary. I like the thumbnail view and the fact that I can create Collections easily on the reader itself.

If you are reading a book, the shutdown can be performed in 4 steps, still a bit labourious but I have to admit that I don't bother, anyway, and leave the reader on a standby. I haven't had time to play with the reader as much I want to so I haven't tested the extra functions like handwriting or adding memos. The look-up dictionary within the text works well enough although in one of the .pdfs it was impossible to highlight only one word so the dictionary had a bit of a problem with a string of words! Must have been the file as other .pdfs I had tried were fine.

The few.pdfs I have tried seem to work as well as expected on a 6" screen, I guess a wider selection of font sizes will help but really only a bigger screen will show them as they are supposed to look, in a font size which can actually be read easily! I haven't tested the reader with a 60 Mb file which froze my 505 yet.

I haven't tried the stylus; to be honest, I don't see myself using it very often. The same goes for the MP3 player.

I am very, very happy with the 650 and very glad that I didn't get the Kindle. And I really, really need a cover for it, the reader seems so vulnerable without it!