I have been using a kindle keyboard (3.5) since January 2011 (still use it actually). It took until September 2012 for them to introduce what they call "crisper fonts" which were fonts that actually match the pixels of the device. This means that before "crisper fonts" the same letter could look different depending on its position (which was not aligned with the pixels). I have for that entire 20 months wondered if anyone at Amazon actually used the kindle themselves.

Other than that I'm still quite pleased with the thing (apart from the small trouble of having to remove DRM from most books to read my, paid for books on unsupported devices. Calibre plugins make this quite painless thankfully.)