It is a no-go on the iPhone 3GS, you need the iPhone 4’s A4 processor (iPad version por favor?) and probably its higher res screen as well.   Handling video and creating real-time transitions was the official reason.   You can’t export projects (yet?) to iMovie on the Mac for further editing.  Obviously you can export via iTunes flat movies and do whatever you want on the desktop after that. You can record video and still directly within the application or bring in previously recorded stills/videos.  Because of the way the iOS works, you can also use footage sent to you via email because image/video files are saved in the Camera Roll.  Obviously the files would need to be Apple-approved formats like H.264.  .AVIs need not apply. The app will ship on June 24th for $4.99 (known already).  The app is for iPhone only because it probably uses the higher res display and probably won’t upscale to the iPad’s display.  It would be surprising if a iPad version doesn’t at some point ship, whether the iPad gets a camera or not. 

For $5, this app seems like a no-brainer.