The stock is limited to only a single model each, and based on past experience I would bet the supply is probably also limited to whatever Amazon happens to have on hand. So if you want TTS or a keyboard on your ereader, act fast.
The Kindle Keyboard available at the moment is equipped with both 3G and Wifi. What sets it apart from the new Paperwhite is that it has 4GB of storage, a keyboard, support MP3 and Audible audiobooks, and text to speech. The revived Kindle Touch only has Wifi and 4GB of storage, but like the Kindle Keyboard the KT has audio support.
Both models have (nearly?) all of the software features found on last year's Kindle Paperwhite. I am not aware of a recent update, but I do know that both devices support KF8, Kindle X-Ray, digital comics, Kindle Cloud, and more.
In fact, the last update for the Kindle Keyboard (v3.4) mentions Whispersync for Voice and parental controls. Considering that this ereader is now over 3 years old am frankly surprised that they are still supporting it.