According to an article over on all about Symbian, the Nokia flagship smartphone, the Nokia N97 is in many respects a Nokia 5800 XpressMusic with some nice extras added and is a significant improvement over Nokia’s first touch screen S60 handset.
For example, the Nokia N97 incorporates an eBook reader which uses the Mobipocket mature books reading platform, but this also runs on the Nokia 5800 XpressMusic as well.
The difference with Mobipocket ion the Nokia N97 is if you happen to go full screen you cana return by pressing the * key, however with the Nokia 5800 XpressMusic there is no * key and thus you have to uninstall the app and then reinstall, thus Mobipocket eBook reader is far better on the Nokia N97.