For me the main reason is FBReader. I have used FBReader on multiple devices (Nokia 770, PepperPad 3, Iliad, and now the EZ Reader Basic). It isn't perfect, but it provides a highly customizable and moderately consistent screen layout across multiple devices and multiple DRM-free ebook formats. The
OpenInkpot 0.2 Users' Guide includes a list of FBReader's capabilities and settings.
Other EInk readers now use FBReader, for example the PocketBooks and the Onyx Boox 60 (BeBook Neo), but the Hanlin V3 with OpenInkPot is still an excellent basic ebook reader.
Its only significant annoyance is the lack of filesystem export via USB. Using SSH to copy to/from the device is in some ways more powerful than filesystem export, but both could be supported. This is particularly problematic for Windows 7, see
Gett SSH to work under Windows 7.