The overall rating reflects the current state of the app. It accounts for all app reviews but prioritizes the most recent ones.
Application its self is reasonably easy to use however, I have been requesting help with updating the App Icon and the displayed images within iTunes for weeks on end now and I am yet to receive confirmation regarding this. The after sales support is appalling.
All looks great until you're getting ready for launch, full of bugs and suport don't give a real solution and delay to respond, if you need your app get ready on time, don't use this option. Bad experience