1) no physical page turn buttons, 2) weight, 3) worse typography.
They seem to have fixed (1) in the latest model, but I still need to check if it's as heavy as the paperwhite and whether they improved they way text is displayed.
The Kindles are using internally the freetype library but it is a crippled version. Some fonts make it crash and kerning is apparently compiled out.
That's why the Jailbreak community is distributing their own version of it because otherwise the various jailbreak ereader wouldn't work properly.
Kindle 4: 169.5g, 165 x 114 x 8.6 mm
Kindle Voyage: 180g, 162 x 115 x 7.6 mm, so 6.2% heavier than the Kindle 4, but 12.6% lighter than the Kindle Paperwhite.
See here for a side-by-side screenshot of the same text on Kindle 4 and the Paperwhite: http://screech.rychter.com/files/kindle-4-vs-paperwhite-2014...
Notice how the left screen reads uniformly, like a book, while on the right screen spacings are slightly off, enough to give it a "computery" look.
I'm surprised more people haven't noticed this.
1) no physical page turn buttons, 2) weight, 3) worse typography.
They seem to have fixed (1) in the latest model, but I still need to check if it's as heavy as the paperwhite and whether they improved they way text is displayed.