I'm still quietly rooting for an E-Ink resurgence. Platforms like this and the E-Ink phones announced recently are great to see, something about E-Ink's simplicity is just so damn charming.
I don't understand why the server is needed. Can you use it without the server?
Big e-ink fan, but having an intermediary server like that should really lead to the devices being much cheaper, which I guess is an economies of scale problem.
On one side, the Visionect stack saves you insane amounts of money over trying to develop against vanilla Eink hardware. Which has to be worth something, right?
On the other side, VTablets are a lot more rugged than your vanilla ebook reader (which are cheap consumer devices).
On the third side, support and R&D. The devices and the ecoystem is constantly improving and evolving. This is not a consumer device with a single use case. Also try calling Amazon about getting some help from them regarding deploying your app to their device.
On the fourth side, economies of scale like you noticed yourself.
Disclaimer and shameless plug: I was part of the Visionect team and was involved with development of Geoffrey eMenu and Wemar Nautipad applications.