You may well be asking yourself what possible benefit a decade-old plastic word processor with a four-line calculator-style display and for the love of Pete, not even a cut-and-paste feature could possibly have for a writer. My answer to that is: "bang! You're writing."
Computer word processing programs are wonderful: don't get me wrong on that count. But they come on computers, which means that they take several minutes to start up and then load the document in question (and longer if you have a slow-booting monstrosity like many of us have), and they are absolutely bristling with distractions: games, e-mail, the Web ... honestly, how often do you start up a computer and do nothing at all apart from writing? On an AlphaSmart, writing is all you can do. You pick up your AlphaSmart, and literally two seconds later, you're staring at a the blinking cursor, ready to type.
And you can write virtually anywhere on an AlphaSmart. I've owned mine for only a week, and already I've written in a cramped airplane seat with the person in front of me leaning all the way back, held in one hand while walking down the street, in a chair with the AlphaSmart sitting on my crossed legs, in bed, on a bannister beside a restaurant door as I thought of an idea on the way out ... well, I could go on, but suffice it to say that in cramped spaces, brief windows of time, locations with no flat surface, and many other situations that would not work with a laptop, an AlphaSmart will let you write. In fact, you can use an AlphaSmart pretty much anywhere you can use a pad of paper, with the improved writing speed and electronic availability of a digital file instead of a page full of ink for your trouble.
AlphaSmarts are also easier to carry around than laptops, weighing about as much as a hardcover novel and being only about 50% larger. They're rugged, they save your work automatically, they can be turned on or off at a moment's notice, they offer eight files to switch between at the touch of a button, they run hundreds of hours on a few AA batteries, they find and spell check, and they will dump information (albeit slowly) to either a PC or a Mac. Having an AlphaSmart means that within moments of thinking "Hey, I could do some writing right now," I can actually _be_ writing. Oh, and AlphaSmart 2000's go for less than $30 used on eBay.
They're not perfect for everything. For instance, only in a special circle of Hell would a person do substantial edits on an AlphaSmart, given the slow scrolling and lack of cut and paste features (although the newer AlphaSmarts have more features, like built in typing lessons, dictionary, and thesaurus as well as cut and paste--which still would not make it a joy to edit intensively on them). Yet this isn't a complaint: AlphaSmarts, as far as I'm concerned, are for cranking out words, not for editing or any other writing-related activity that doesn't involve clattering away on the desktop-style keyboard.
You don't necessarily have to buy one of the old AlphaSmart 2000s. The newer Neo has the niftier features I mentioned while still retaining all the benefits of the older AlphaSmarts, and the Dana is essentially a Palm Pilot in the form of a big keyboard and a wide screen. For what I do with them, though, an old AlphaSmart 2000 is perfect. Even pads of paper allow you to doodle: the AlphaSmart, in a way, is the ideal object on which to just plain write.
LITTLE TECHNICAL NOTES: To transfer files between an AlphaSmart and a Mac or PC, you need to buy a cable that plugs into the computer as though the AlphaSmart were a keyboard--and in fact, an AlphaSmart can be used as a keyboard if you like. Once connected, you send the file from the AlphaSmart and have to wait while it appears on the screen as though it were being typed by a supernaturally fast typist. You can buy a special cable depending on whether you use a PC or a Mac, or you can do what I did and get a Male PS2 to Male PS2 cable and connect that to a PS2 Female to USB converter (about $16 at RadioShack, and please note that the little green kind that look like they should do the job don't work for this purpose). This allows you to plug your AlphaSmart into either a Mac or a PC, as you like. Or, if you have an infrared-capable AlphaSmart and your computer has an infrared port (it looks like a little black plastic window), you can send information back and forth to the AlphaSmart by infrared, skipping the cable altogether.