It was little things like, "Note that there is nothing to show that you are actually recording a message, and if you don't stop recording, you'll fill up the file-system eventually" that made me say that DT-Talkie is proof-of-concept level still. There are no cues to tell you what button to push in the app itself, and no cues to show that anything is being done...

EDIT: Here are some more things that make this a rough-edged app:

There is also no way to delete contacts, and contacts that are discovered by your tablet are not added to your list or shown in the GUI in any way...