The AlphaSmart Neo is a neat little writing tool that is basically a stripped down, very bare bones laptop. It weighs less than 2 lbs, can go 700 hours on just three AA batteries, has a keyboard only about an inch narrower than a laptop (still bigger than those mini laptops, such as the Asus eeePC).
I learned about the AlphaSmart during NaNoWriMo a couple years ago, and I just got one last October. Participants in NaNoWriMo use the AlphaSmart for writing their novels, and it certainly does help with getting writing done fast.
The screen is small (5.75"x1.5" LCD screen) which can accompany up to six lines of text at a time. That sounds very small, but it isn't as bad as you think. If you are the kind that tends to go back an edit what you've written a lot, the smaller screen could help you control that and get to writing faster.
I still use my laptop for writing stories because I like to see a whole page at once (helps with my visualization in my mind, though I can't explain that). However, I use my AlphaSmart NEO for taking notes, and it works better than anything for that. Since I type faster than I write, the NEO really helps me get my thoughts down quickly so I can get back to whatever it was I was doing. The NEO powers up in only four seconds (I timed it. From the time you press ON to the time you are ready to start typing is four seconds) which is 15 times faster than my laptop.
Not only that, the NEO saves automatically. As soon as you type it, it is saved. So I can turn it on, wait four seconds, type my notes, whatever they are, then immediately turn it off. Turn it back on and I can write where I left off. It's lightweight, making it portable, and the keyboard feels good to use and makes a satisfying clacking sound (I know you know what I mean).
The NEO would be more convenient for writing on the go than a laptop, such as writing during a subway commute, or in a coffee shop, whatever. The NEO, however, is not more versatile than a laptop. It does have spellcheck and a thesaurus, but the NEO is in essence a one-trick pony. But it does that trick exceedingly well.
The 700 hour battery life on just three AA batteries is no exaggeration. Mine is still on 95% and I got it last October (though I don't use it everyday).
Here is a link to a .pdf file explaining the NEO, and
here is the website. It's $219. Last year, AlphaSmart had a promotion with NaNoWriMo where you could get $20 off. I don't know if they are going to do that this year.