Can only compare the Nook and the Sony PRS-300. I have a PRS-300 and a friend has the Nook.
The Nook is a nice big device with a clear screen. The latest firmware now includes a chess game and a Sudoku game. Buying books directly from the device is nice if you travel. The onboard memory is massive.
Negatives. It feels slow. It is a bit heavy and big, more like a hardcover than a paperback. The touchscreen interface is less intuitive than you might expect. The page change buttons are in a somewhat inconvenient place and they are take a hard press. B&N uses a non-standard authentication system, so some store bought Epub books may not work.
PRS-300.
This was my choice primarily because it is small enough to really carry. I know this isn’t one of your choices.
Positives:
Very small and light. Excellent reading ergonomics. The control pad in the center is well positioned for right or left handed use. I wanted small and minimalist and that’s what this is.
Amazing battery life. Forward and back page turns are easy without changing hand position. There are a wide variety of sources for books and with a little searching, they are almost always the lowest price available. The Epub format is industry standard.
The Sony readers are compatible with the ebook borrowing system many libraries now have. This lets you check out ebooks from the library.
Negatives:
Small screen may not be optimum for some people. Only charges with USB when plugged into computer AND connected to Sony software. Beyond that, you would need a Sony Reader or Sony PSP adapter. Sony sofware is pretty bad and the default Sony store is overpriced.
It’s minimalist. No onboard book purchasing and the price needs to drop to about $99 to compete.
A couple general ebook suggestions.
inkmesh.com is an ebook search engine and price comparison site. It can help you find the best available prices.
Calibre is book managment software that is much better than any bundled software. It also lets you download blogs and newspaper sites from the net and formats them for easy reading on an ebook reader. http://calibre-ebook.com/
The "ePaper" display is a real battery-miser compared to an LCD -- we're talking several multiple DAYS of use (or longer), compared to a few HOURS for an LCD device. It is the least eyestrain-inducing display medium. (All of the popular readers use the SAME actual ePaper display, BTW.)
Unlike the high-priced/big-name readers, the Sony is METAL, and, unlike most readers, it accepts a wide variety of ebook formats.
Better yet, with the free "calibre" ereader management suite -- MUCH nicer than the official software -- you can convert nearly ANY ebook format, and load it onto the reader (it supports a variety of readers, not just the Sony) -- or, download hundreds of newspapers, magazines, etc, and load them into the reader).
It has fantastic organization tools, a very well-thought out database, and makes ebook management unbelievably easy -- I downloaded it after reading one post after another by people raving about how good it was -- and they were telling the truth.
I have a total of six bucks invested in content -- I bought one book from Baen (Live Free or Die -- a "first contact" SF novel) -- all the rest are thanks to stuff like Gutenberg and the Baen free library. I'll probably buy a few more books, but there is SO much excellent stuff in the public domain (and, in the case of Baen, non-public domain, but, given away as free advertising for their other stuff).
To everyone saying why buy an e-reader when you have a laptop, the answer is obvious to anyone who's used both types of devices -- a laptop is big and heavy and cumbersome, compared to an e-reader (my Sony, with the big screen (they have a smaller pocket-size model too) is approximately the size of a THIN paperback book. My laptop? NO comparison!
Plus, the laptop eats the battery like it's going out of style, whereas the Sony just keeps on keeping on.
A device smaller than a typical paperback book, able to hold hundreds (thousands, if I pop in a five dollar memory card), weighing a few ounces, with a battery life that's just bleepin' unreal... or, a big, heavy laptop, with a bulky screen, a huge keyboard, a battery-eating processor, memory, disk, display....
NO contest!
bkmk
I heard that Google is releasing an e-reader some time this summer, I want to wait and read the reviews on it before I decide.
We just got a Nook...battery is user-replaceable, it has micro-SD memory card support, but I was a little disappointed to learn that it requires removing the back cover of the Nook to add the memory card (no slot), and was fairly tricky to install. I will be using USB to transfer files from now on...(leave SD card in it permanently).
The “read-in-store” feature is nice (if you have a B&N “brick & mortar” near you), it allows you to read any/all e-books available for 1 hour per day in store on their Wi-Fi.
We like it so far!
For me, Kindle, hands down. The “Wispernet” connectivity allows you to download books (and gives limited internet access) ANYWHERE! Without any connectivity fees. Without having to hook up to a computer.
Amazon alone has more than 30,000 books FREE, before you even get to Project Gutenberg.
Device becomes very natural in your hands, so much so that (strangely) I prefer it to actual books. In general, it is very cool to have (up to ) hundreds of books already downloaded and waiting for you, any number of which are opened to your last page read, in one small device. I love being able to read “Plato’s Republic” or “The Lightning Thief” in a waiting room without a book cover to advertise the extent of my nerdiness!