The description says you get unlimited tweets. You have the ability to send tweets, get replies, retweet, exchange direct messages and download followers. I am not sure what downloading followers means.
The device has a full QWERTY keyboard and a color screen. The battery life is supposed to last four to five days only take two hours to recharge.
Is anyone really that much into Twitter that they would have to have a device like this? Every smartphone has multiple Twitter clients to choose from and you can always use the Twitter web site with just about any mobile browser. For people you really must follow in real time, you can just configure their tweets to go your SMS inbox.
We'll just have to wait and see how popular this device becomes. It says it is the worlds first Twitter mobile device. My gut says it is the last. Maybe I am wrong. Maybe there are more people out there with $8 to burn each month to access Twitter in real time, all of the time.