The benefits of Sony's Digital Paper E Ink tablets are clear with the DPT-CP1. It has an excellent, highly readable 1,404 x 1,872 black and white screen, but is just 5.9 mm thick, weighs about 8 ounces and can go a month on a single charge. It also has a certain x-factor, thanks to the stylus and ability to let you read, jot, sketch and work in longhand on a more paper-like screen than other products.
The problem, however, is the price: It costs 70,000 yen (around $650). That's $100 less than the 13.3-inch model, but it's still not an impulse purchase like, say, a Kindle. It's an interesting product, though, so hopefully Sony will keep making them, and making them cheaper. In any case, it's only available in Japan and isn't likely to come to North America.