Pros: Battery life, design, screen
Cons: top heavy, fragile, buttons
First the Kindle, second the audio
The Kindle is great if you like to read. It looks like a read piece of paper in front of you while also not being a book. I use mine to read translated Light Novels and Manga.
You can place PDF or use the converter Calibre to convert PDF over to the Epub and the kindle can use it's full features. The features include: It reads to you, size font and size of text area, motion the text side to side and note and bookmarks for later. PDF can't do as much and I was lacking this.
To read manga on a kindle, you use Mangle (oooooo, the name) to put the manga .jpg into a imag book form so the kindle can read. Nice feature but best on the DX kindle.
The UI is trash, but much more usable then the Cowon's UI. Buttons are shallow and hard. I'd like to see touchscreen sometime in Kindle 4. The battery is at the top so top heavy and it's too thin to take out of the expensive kindle case. But the case is nice. MAKE SURE TO BUY THE KINDLE FLIP OVE CASE MADE FOR THE KINDLE. not a slip over, it makes a difference.
Audio is subpar. The feature was a throw in. I loaded up a couple low quality albums to save space and I play when I don't have music already going.(quite rare). On board power if more then a NDS but less then a Sansa. Cna push my HD598 well but not loudly. The speakers are nice though. Coming from extra flat low power speakers, they give a soundstage and some bass impact loose while also letting the treble play clearly and some mids separation. Grain of salt here.
Overall: Great to read and to get free classics and whatnot online to put on. Not very good to buy a book every now and then. If you do read, it will be a lot better then to buy a collection. But you also lose the library you wanted to grow. Otherwise saves money they also. Buy this for the reading and also check out the audio, not the other way around.