I'm considering getting a zaggsparq for when I will be on the road, or gone for 12+ hours or when I know I will have some extensive use. I have done some testing as well and with 3g network:

- 2nd full charge of the device, before that I used it plugged in as I don't have my screen proctectors and I'm sick with flu resting at home. I have used it for 6 days though, and pretty much installed lots of applications from the extras, and a few from extras-testing.
- facebook widget disabled, weather widget, and some others active.
- 3g network online (but inactive), no wireless
- some browsing 30minutes (gmail, facebook, maemo forums and no flash content if I remember correctly)
- little talking maybe 5 minutes
- IM services and email offline
- network search offline
- took 3 photos
- recorded a 45 second video and broadcasted it via qik
- Desktop widgets set to update every 4+ hours
- some gps used due to pictures/videos taken wşth geo-tagging

I got around 17 hours of battery life.
Now with extreme (but planned) using, I bet that this device can take 7-8 hours at most, which is not that bad actually considering that during the day most people get a chance to plug it someplace.

I have not tested battery life with videos or mp3s, but I bet the device can handle media without issues and it's the radios that cause most issues.