I spent some time today with Hemingwrite co-founder Patrick Paul, and he let me play around with one of the prototypes. It was a fun device, and even though the software was obviously in a state of flux and the prototype used components which may not make it into the final product, I could see that a lot of thought went into it.
The Hemingwrite is actually designed to be a far simpler device than I had been expecting. While I call it a word processor and it is running software which is similar to what you might find on one of those outdated devices, the Hemingwrite is actually intended to be closer to an even more outdated device: a typewriter.
The Hemingwrite is running complex software, yes, but the software is being designed to limit the operations. For example, the three "folders" indicated by the switch on the left side would better be described as "stacks". There's no actual folder structure nor can you view the file names; instead you get to tab through each of the open files in one of the folders, just like you would flip through a stack of paper notes.
The other software features show a similar design intent to intent to limit what you can do with the Hemingwrite. For example, there's no way to move back and make a correction short of using the backspace key to delete everything (and they're not planning to add one). I was told that the idea was that the Hemingwrite is intended for _writing_, and not editing, and so the user was limited to going forward rather than going back.
I could write more about the software features, but since the software is described as being incomplete I won't go into further detail here.
Edit: But I should probably note that one or more of the upper KS tiers do entitle you to an SDK. You can write your own software for the Hemingwrite.
Physically, the Hemingwrite is as blocky as it looks. The prototype I used had a shell made from milled aluminum, so it was considerably heavier than the production units will be, but since I didn't have an opportunity to vamoose with the prototype that doesn't really matter.
It is a very simple design with a switch on the left of the 6" E-ink screen (folders), a switch on the right (Wifi), a power button, and the keyboard. This last was sourced from another device (the spacebar was scratch built, which is why it looks different), and was still labeled for functions not supported by the Hemingwrite. In addition to the number row and the qwerty keys, there are several keys which might end up being mapped to various functions, but aside from the one print/send function key that is still up in the air.
In use, the keyboard was as nice as you would expect from a mechanical keyboard (although small). I usually type on a full-sized USB keyboard which feels mushy in comparison to the Hemingwrite, although mine might be healthier for long term use.
I noticed while typing that the design of the Hemingwrite is likely going to cause wrist problems. Due to the thickness of the Hemingwrite's base, the keyboard is position in such a way that my hands were angled upwards while I was typing. That is a position you're supposed to avoid because it puts stress on your wrist and could lead to carpal tunnel syndrome.
I would expect that Hemingwrite owners will want to buy a wrist pad to place in front of their unit, if they don't already have one for their computer's keyboard.
All in all this was a fun toy, but I'm not sure that the problem it is trying to solve justifies the $500 price tag.
If you think it does, you can pre-order one on Kickstarter for $400. It is expected to ship in September, although I would bet for one reason or another (FCC, manufacturing delays, redesigns) it won't ship until next March at the earliest.
P.S. I'm betting that the Hemingwrite will be redesigned to include a protective shell for the keyboard and screen. As I sit here thinking about it, I don't think anyone is going to want to carry it around loose like it is. That's not how we carry laptops today, and it's not how portable typewriters were carried (they had cases) for the simple reason that these devices are easy to damage.