Asus EeeNote EA800: 8-inch screen, unfortunately monochrome LCD, not e-ink - otherwise the best device I have used so far. Here is a summary of the devices I have used and my experience: Not all devices support all of these functions.
For example, my workflow involves writing, erasing, inserting and deleting pages, saving notes, renaming notes, searching notes by key words in the title, sorting notes, editing notes after saving, making backup copies, and converting notes to pdf when I migrate to a new device. Software: depending on what you want to do and how frequently, some devices will fit you better than others. Camera: if the device has a built-in camera, you can snap a photo of the whiteboard or a document and embed it in your notes. Sound recording: if you want to use the tablet for meetings or lectures, sound recording can be useful. Screen size: ranges from 5 to 10 inches, should be an important factor in your choice. The small Sony devices (T1, T2, T3) don't have this technology so I would not recommend them. This allows the screen to ignore your hand and avoid unwanted marks. For accurate and comfortable handwriting, the device should have an "active digitiser" in the screen (Wacom or similar). I don't like taking notes on backlit color tablets, because the light hurts my eyes. Monochrome LCD also works, but it has less contrast, so you need good lighting.
There is nothing wrong with e-ink for note-taking, the screen refreshes only at page turns, similar to reading.
I have researched this subject to some extent.