I wouldn't really be able to compare it to Siri, given that I've never met her. But I can note that Edan doesn't speak, so it wouldn't be fair to compare this app with Siri. I think it would be better to compare Edan to the virtual assistant on the Samsung Galaxy Tab. I've used that one extensively, and like Edan it doesn't talk.
I didn't have one of Ematic's tablets at hand, so I test Edan on the Innosoul tablet I got just over a week ago. It worked okay. For obvious reasons it wasn't as well integrated as the Galaxy Tab app is on that tablet, which has its own button on the on-screen keyboard.
In order to use Edan you need to have the app open. From there you can use voice commands to search the web, send emails, open other apps, and you can update Twitter and Facebook. I don't have either social network configured on the Innosoul, so I wasn't able to test it.
But I did all the rest, with a moderate degree of success. Some of the app names (ie Aldiko) stumped Edan, but the simpler names like Angry Birds were recognized just fine. The speech to text dictation worked much the same as the app on the Galaxy Tab; it stumbled over the more complex names and required me to state the punctuation.
Edan wasn't quite as accurate as the other app, but then again that app was developed by Samsung for their hardware, and Samsung had lots of money to throw at the problem. Edan is running on a tablet I just happened to have sitting on my desk, using a microphone of unknown quality. You should also note that Samsung's app was never better than about 85% accurate itself, based on my experience with it.
And Edan did work well on the more basic words. I had to relearn how to speak clearly so I would be understood, but then again I spoke in much the same way when using the Galaxy Tab app.
All in all, Edan is not a bad app. And it's definitely a selling point for the Ematic tablets. You might have to use the app before you realize the value, but I have come to like not having to type short emails and tweets via the onscreen KB. Dictation is just nicer.
P.S. I'm not sure which tablets ship with similar apps, but I don't think it's that common. My Asus eeePad Transformer did get this in an update late last year, and the only other tablets that I know have it are all rather pricy. Does anyone know of a budget tablet with voice recognition?